intermediate algebra

[hopen2impov]

add, -5+(-40)

 

[Deleted member 4993]

add, -5+(-40)

Please show us your work, indicating exactly where you are stuck - so that we may know where to begin to help you.

 

[Denis]

add, -5+(-40)

If you're REALLY "hoping to improve", sure won't be done if we just give you the answers.
Are you attending math classes?

 

[hopen2impov]

yes, i am struggling

add

-5+(-40)
-5-40
answer 45, is this correct.

(-8)+(-17)+(-3)+14
(-8)-(-17)-(-3)+14
-8+17+3+14
9+3+14
answer 26, is this correct

subtract

-14-(-4)
-14+4
answer 10, is this correct

 

[Deleted member 4993]

yes, i am struggling

add

-5+(-40)
-5-40
answer 45, is this correct. <<< almost - not quite. The answer should be -45 (with a negative sign in front)

(-8)+(-17)+(-3)+14
(-8)-(-17)-(-3)+14 <<< Do NOT change those signs

(-8)+(-17)+(-3)+14

= -8 -17 -3 + 14

= -25 - 3 + 14

= -28 + 14

= -14



-8+17+3+14
9+3+14
answer 26, is this correct

subtract

-14-(-4)
-14+4
answer 10, is this correct <<< Yes and No - you forgot the negative sign in front of 10 - so it should be -10

 

[hopen2impov]

at first i change the signs but after that keep them?

ok, i will try this one again

17+(-7)-(-1)+11
17-7+1+11
10+1+11
11+11
22
answer 22, is this correct

-14-(-4)
-14+4
-10
answer -10, is this correct i notice a mistake i had made with the signs

i'm going to redo this one again, let me know if i'm right, ok

(-8)+(-17)+(-3)+14
-8-17-3+14
-9-3+14<<< That should be -25 . Look at my work above
-12+14
2
answer 2, is this correct

 

[hopen2impov]

i understand, even if both numbers are negative i still add and keep the signs, do i subtact when one is negative and the other is positive taking sign of the biggest number?

(-8)+(-17)+(-3)+14

-8-17-3+14
-25 add but keep the signs, -3+14
-25-3= -28+14
-14, does it seem like i understand this one?

multiply

(-126)*0=0

(-3)(-4)(-6)(-8)(-10)(-13)=
answer -74,880, is this correct?

divide

-136/-8
-8/-13 is 1 and -8/56 is -7
answer -17

8+16*(2+18) divided by (-10)
8+16(20) divided by (-10)
8+320 divided by (-10)
8+32
40
answer 40, is this correct.

3/4 divided by (-7/13)
i don't know what to do, how do i start with this one?

-5[-2+3(5-8)]
-5[-2+3(-3)]
-5[+1(-3)]
-5[-3] is this the answer or do i loose the bracket and keep the () and keep going, like this?
-5(-3)
-15

 

[hopen2impov]

will i be able to get some help with the rest of my math problems? How ofter are the math problems answered?

 

[mmm4444bot]

How ofter are the math problems answered? The volunteers at this site do not follow any schedule. Confusing posts sometimes get ignored.

(-8) + (-17) + (-3) + 14

-8 - 17 - 3 + 14

-25 add but keep the signs, -3+14 Please do not insert English words into the middle of your arithmetic; that's confusing.

Type it like this: -25 - 3 + 14

-25 - 3 = -28 + 14 This equation is false! Why did you write an equation, anyway?

Write the next line like this: -28 + 14

-14 This is the correct answer.

does it seem like i understand this one? I think so, but the way that you wrote your steps is confusing.



multiply

(-126)*0 = 0 This is correct. Any Real number times zero is zero.



(-3)(-4)(-6)(-8)(-10)(-13) =

answer -74,880, is this correct? No. The sign is wrong.

Every pair of negative factors produce a positive product.

Or, you can factor out all of the factors of -1, and think of it like this:

(-3)(-4)(-6)(-8)(-10)(-13)

(-1)(3)(-1)(4)(-1)(6)(-1)(8)(-1)(10)(-1)(13)

(-1)(-1)(-1)(-1)(-1)(-1)(3)(4)(6)(8)(10)(13)

Six factors of -1 multiplied together equals +1.

(1)(74880)

74880



divide

-136/-8

-8/-13 is 1 No, it is not!

-8/(-13) = 8/13

and -8/56 is -7 No, it is not!

-8/56 = -1/7

answer -17 The answer must be positive because a negative divided by a negative is always positive.

I don't follow your reasoning above with -8/(-13) and -8/(56), but the correct answer is 17 because 8 divides into 136 seventeen times AND a negative divided by a negative is positive.



8 + 16*(2 + 18) divided by (-10) I'm guessing that this means: 8 + 16*(2 + 18)/(-10)

8 + 16(20) divided by (-10)

8 + 320 divided by (-10)

8 + 32 This should be 8 - 32 because 320/(-10) = -32

(A positive divided by a negative is negative.)

The correct answer is -24.



3/4 divided by (-7/13)

how do i start with this one? Use the following rule, for dividing by a fraction:

a/b divided by c/d is the same as a/b times d/c

In other words, multiply the fraction on top by the reciprocal of the fraction on bottom.

Example: 1/2 divided by 4/5

1/2 * 5/4 = 5/8



-5[-2 + 3(5 - 8)]

-5[-2 + 3(-3)]

-5[+1(-3)] This is not correct.

In the second line above, we have -2 + 3(-3) inside the square brackets.

The Order of Operations tells us to do multiplication before addition.

Therefore, we need to multiply 3(-3) before adding -2

Can you fix this error, and then continue?

 

[Deo3560]

Well this is what I have learned,

"Add a line change the sign, follow the rules of addition."

So if it was 16-(-24), you would "add a line" on the subtraction symbols, (making a addition symbol) which is changing the sign. Then you just add them.
So 16-(-24) will turn into 16+24, then 40

If it is a negative and a positive, such as 16+(-24), the 2nd number is the number you will be using, so it will change into 16-24, then -12.
If it was 24+(-16), you still subtract making 12, but this time positive. It isnt about the size of the number, just using the right sign.

Then there is order of operations, which is
(P)arenthesis -> (E)xponents -> (M)ultiplication -> (D)ivision -> (A)ddition -> (S)ubtraction
Which is PEMDAS

And you also work from the left to the right if there is more than 1 of the same operation.

 

[mmm4444bot]

"Add a line change the sign, follow the rules of addition."

Are these lyrics from some song? Was your instructor dancing around the room, singing, when they taught you this?

16+24, then 30 This is obviously incorrect.

there is order of operations, which is
(P)arenthesis -> (E)xponents -> (M)ultiplication -> (D)ivision -> (A)ddition -> (S)ubtraction



Correct. Multiplication is done before addition.

-2 + 3(-3)

You need to multiply 3(-3) before you do the addition.

-2 - 9

-11

Unless you have a specific question regarding any of your mistakes that we've pointed out, so far, I'm done here.

 

[Deo3560]

Oh yeah, I'm stupid, the 30 part was my mistake, It's 40 >.<.

Yeah, it was said as a song and the teacher put hand motions with it =P

 

[hopen2impov]

HELLO

(-55.7)+27.6+(-3.4)
-55.7+27.6-3.4=
-28.1-3.4=
answer 31.5 is this correct?

subtract

(4/7-(-5/8)
4/7+5/8
4/7/56+ 5/8/56
32/56+35/56
answer 67/56 is this correct?

multiplying

(1.8)(-4.38)
answer -7.884 i think this is correct, is it?

1.5*(-2.3)*5
-345*5
answer 17.25 did i get this?

divide


(2/5)/(-1/2)
2/5/10-1/2/10
answer 9/10 i'm scared to ask but is this correct?

 

[mmm4444bot]

(-55.7)+27.6+(-3.4)
-55.7+27.6-3.4=
-28.1-3.4=
answer 31.5 is this correct?

The three lines of work shown are correct, but the answer is not 31.5 (check your arithmetic on the third line).



(4/7)-(-5/8)
4/7+5/8
4/7/56+ 5/8/56 This line is incorrect. We do not divide each fraction by the LCD.
32/56+35/56
answer 67/56 is this correct? This answer is correct.



(1.8)(-4.38)
answer -7.884 i think this is correct, is it? Yes. For checking, do you have access to a calculator ?

1.5*(-2.3)*5
-345*5 I think you forgot to type the decimal point, on this line.
answer 17.25 did i get this? No. A negative times a positive is negative.



(2/5)/(-1/2)
2/5/10-1/2/10 We do not divide the fractions by the LCD, and why did you change from division to subtraction?
answer 9/10 i'm scared to ask but is this correct? No. Use the rule that I showed you, for dividing by a fraction.

 

[hopen2impov]

1.5*(-2.3)*5
-3.45*5=
answer -17.25

(-55.7)+27.6+(-3.4)
-55.7+27.6-3.4
-28.1-3.4
answer -31.5

2/5/-1/2
the only way i know how to do this is to divide by the LCD. i'm really weak in this area. Don't be mad at me. i know the LCD is 10, now what?
is the answer -1/10 by finding the LCD and add.
2/10-1/10= -1/10 if this isn't correct, i don't know!

simplify

-12+7^2-(7)*2
-12+7^2-14
-12+49-14
61-14
answer 47 is this correct

5^2*(-10)+(-11)*8
25*(-10)-11*8
-250-88
-338 is this correct?

5*(-8-1)+3*(-7)
5*(-9)+3*(-7)
-45-21
answer -66 is this correct?

4*(2+3)^2-3*(5-3)^2
4*(5)^2-3*(2)^2
4*25-3*4
100-12
88 is this correct?

what in the world!

4m^2-2mn+3n^2-8(2m^2+4mn-9n^2)
4m^2-2mn+3n^2-8(4m+4mn-81n)
4m^2-2mn+3n^2-8(8m^2n-81n)
4m^2-2mn+3n^2-8(-73m^2)
16m-2mn+9n-8(-73m^2)
14mn+9n-8(-73m^2)
23mn^2-8(-73m^2)
15mn^2(-73m^)
-1095m^3n oh please tell me if this brain buster is correct?

 

[hopen2impov]

ok, i redid my thinking

4m^2-2mn+3n^2-8(2m^2+4mn-9n^2)
4m^2-2mn+3n^2-8 2m^2+4mn-9n^2
2m^2+4mn-9n^2-8
6m^2+2mn-6n^2-8
answer 6m^2+2mn-6n^2-8 is this correct or close?
My mistake i took the square as an exponent, sorry. I'm learning from my mistakes. Please don't give up on me...

-2x^2+9x-3(x+3x^2)
-2x^2+9x-3(3x^3)
3x^3+9x-3
answer, i hope x^2+9x-3 i tried combining like terms the first time but it didn't look right, so i tired it this wasy.

evaluate

(6x)/(10x^2) for x=5
65/105^2
answer 169

evaluate

3x-6x^2/x^2-10 for x=-1
-31x-61x^2/-1^2-10
-31x-61x^2/-1-10
answer 30x^2-11

 

[Denis]

4m^2-2mn+3n^2-8(2m^2+4mn-9n^2)
4m^2-2mn+3n^2-8 2m^2+4mn-9n^2
2m^2+4mn-9n^2-8
6m^2+2mn-6n^2-8
answer 6m^2+2mn-6n^2-8 is this correct or close?

That's still so bad we should give up on you...but we won't...YET :wink:

You've got: -8(2m^2 + 4mn - 9n^2) ; that's REALLY simple; multiply what's inside brackets by -8:
-16m^2 - 32mn + 72n^2
So you now have:
4m^2 - 2mn + 3n^2 - 16m^2 - 32mn + 72n^2
Which simplifies to:
-12m^2 - 34mn + 75n^2 ; that's it, over and out :idea:

QUIT complicating things, hear?

Now settle down and try this one:
7(3a^2 + 2ab - 4b^2) + 5(-2a^2 - 3ab + b^2)

 

[mmm4444bot]

(6x)/(10x^2) for x=5
65/105^2
answer 169 65/105^2 is way off, but, regarding how you evaluated it to get 169, I'm stumped !

65/105^2 = 13/2205

(65/105)^2 = 169/441

Uh oh! :shock:

It appears that you're operating under a gross misunderstanding.

The expression 6x does NOT mean a two-digit number whose first digit is 6.

Likewise, the expression 10x does NOT mean a three-digit number whose first two digits are 1 and 0.

6x means implied multiplication: the number 6 times the number x.

10x means implied multiplication: the number 10 times the number x.

(If we were to express these multiplications explicitly, then we would write them as 6*x and 10*x.)

When x = 5:

6x = 6 * 5

10x^2 = 10 * 5^2

Also, note the difference between the two expressions 10x^2 and (10x)^2:

10x^2 = 10 * x^2

(10x)^2 = 10x * 10x

Without the grouping symbols, the exponent 2 applies only to the number x. (Order of Operations)

evaluate (3x - 6x^2)/(x^2 - 10) for x = -1

I will rewrite the given algebraic ratio for you, expressing all of the multiplications explicitly.

(3*x - 6*x*x)/(x*x - 10)

Now, replace each of the five symbols x with the number -1, and then follow the Order of Operations.

I welcome specific questions.

 

[hopen2impov]

I have a question. if you doing addition and you have two negative signs for example,
-2+(-6)
-2-6=-8 would this be correct when adding two negatives but you keep the negative sign? Also, for multiplication, if you have two negative it's a positive sign, would this be true?

Also, i made some corrections to a the math problems i had sent to you,

5^2*(-10)+(-11)*8
5^2*-10-11*8
25*-10-11*8
-250-88
answer -338, is this correct?

4m^2-2mn+3n^2-8(2m^2+4mn-9n^2)
4m^2-2mn+3n^2-8+2m^2+4mn-9n^2
4m^2-2mn+3n^2-8
2m^2+4mn-9n^2
answer 6m^2+2mn-6n^2-8 is this correct? I notice in the original problem i had sent i counted the squares as exponents.

 

[hopen2impov]

evaluate

(3x-6x^2)/(x^2-10) for x= -1
(3*x-6*x*x)/(x*x-10)
(3*-1-6*-1*-1)/(-1*-1-10)
-3-6/-10
18/-10
answer -1.8 is this it or not?