fractions...have no idea where 7x came from..plzz help

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candy101

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ok so i got this question and i know how to slove it and everything but im lost as of where the teacher got this one number.. so here it is


x+5/x-2 = 5/x+2 + 28/x^2-4


so from that i got ..

x^2+10 = 5x-10+28

but.. the teacher got

x^2 + 7x +10 = 5x-10+28

where the heck did he get 7x from???

thanks,
candy
 
candy101 said:
ok so i got this question and i know how to slove it and everything but im lost as of where the teacher got this one number.. so here it is


x+5/x-2 = 5/x+2 + 28/x^2-4

As posted your post reads:

\(\displaystyle x + \frac{5}{x} - 2 = \frac{5}{x} + 2 + \frac{28}{x^2} - 4\)

But, most probably, that is not what you meant

Is your problem:

\(\displaystyle \frac{x+5}{x-2} = \frac{5}{x+2} + \frac{28}{x^2-4}\)

then you should have written:

(x+5)/(x-2) = 5/(x+2) + 28/(x^2-4)

so from that i got ..

x^2+10 = 5x-10+28 <<< How did you get that? Please show steps.

but.. the teacher got

x^2 + 7x +10 = 5x-10+28 <<< This looks correct - depending what the correct problem is.

where the heck did he get 7x from???

thanks,
candy
Click to expand...
 
candy101 said:
Loren said:
Maybe you want to reconsider (x+2)(x+5).
Click to expand...



what do you mean by that..
Click to expand...

(x + 2)*(x + 5) = (x + 2)*x + (x + 2)*5

(x + 2)*x + (x + 2)*5 = x[sup:1xzz0gwt]2[/sup:1xzz0gwt] + 2x + 5x + 10

Combine like terms...do you see where the "7x" comes from?
 
yes my question is the second one


(x+5)/(x-2) = 5/(x+2) + 28/(x^2-4)

first i Multiple
by all the top number by both the bottom----- (x-2) and (x+2)

then from that i got

x^2+10=5x-10x+28

but the teach got

x^2+7x+10=5x-10+28

and i just don't know how he got the 7x
 
Your problem here is in multiplying (x+5) by (x+2).

The earlier posts showed that multiplied out but you may be missing it.
Are you calculating (x+5)(x+2) = x(x) + 5(2) ?
No, you must multiply term by term.

(5)(6) =(3+2)(3+3)=3(3+3)+2(3+3)=3(3)+3(3)+2(3)+2(3)=30 also.
You must multiply both terms in one bracket by both terms in the other.

So, (x+5)(x+2) = x(x+2)+5(x+2)=x(x)+x(2)+5x+5(2).
Somehow, you're getting -10x instead of -10 on the other side also.

(x+5)/(x-2) = 5/(x+2) + 28/(x[sup:1qw3k63x]2[/sup:1qw3k63x]-4) gives
(x-2)(x+5)/(x-2) = 5(x-2)/(x+2) +28(x-2)/[(x+2)(x-2)]
x+5 = 5(x-2)/(x+2) +28/(x+2)
(x+5)(x+2) = 5(x-2)(x+2)/(x+2) +28(x+2)/(x+2)
(x+5)(x+2)=5(x-2)+28
 

i got -10 now i and 10 but i still dont know how he has the 7x

my answer that i got now is

x^2+10=5x-10+28

but the teacher got a 7x before the 10
and i just can't understand how he got that

i need to combine this equation to get a quadratic equation

like this x^2+2x-8=0
 
chrisr said:
Your problem here is in multiplying (x+5) by (x+2).

The earlier posts showed that multiplied out but you may be missing it.
Are you calculating (x+5)(x+2) = x(x) + 5(2) ? ---- no i am not doing this...if i should do this i would get x^2+10=x^2+10
No, you must multiply term by term.

(5)(6) =(3+2)(3+3)=3(3+3)+2(3+3)=3(3)+3(3)+2(3)+2(3)=30 also.
You must multiply both terms in one bracket by both terms in the other.

So, (x+5)(x+2) = x(x+2)+5(x+2)=x(x)+x(2)+5x+5(2).
Somehow, you're getting -10x instead of -10 on the other side also.

(x+5)/(x-2) = 5/(x+2) + 28/(x[sup:1ecxv4bu]2[/sup:1ecxv4bu]-4) gives
(x-2)(x+5)/(x-2) = 5(x-2)/(x+2) +28(x-2)/[(x+2)(x-2)]
x+5 = 5(x-2)/(x+2) +28/(x+2)
(x+5)(x+2) = 5(x-2)(x+2)/(x+2) +28(x+2)/(x+2)
(x+5)(x+2)=5(x-2)+28
Click to expand...



i did (x+5) (x+2) =====> i got x^2+10

then i did the other side=======> (x-2) (5) and i got 5x-10 and i kept the 28 as is because the bottom term cancel out
 
i redid and idk
if this is how he got the 7x but this is the only way i could get it


first i did ======> (x+5) (x+2) i did each term====> X times x, x times 2, 5 times X, 5 times 2

giving me ====> x^2+2x+5x+10 ====> this is just for one side of the problem

so i combine the 2x and 5x getting the 7x? is this the correct way to do it?

so my final answer came out to be (after combing the 2x and 5x) ======> x^2+7x+10=5x-10+28
 
candy101 said:
so my final answer came out to be (after combing the 2x and 5x) ======> x^2+7x+10=5x-10+28
Click to expand...
CORRECT!!
Now solve that for x.
 
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