need help

G

Guest

Guest
I have tried this problem so many times, and can't get it.... :cry:

3(x+y)=-2y-7
-3y=10-4x

Anybody that could tell me how to do this and show me the way to do it would be great....it is an example question....so.....
 
What you've shown: is that your work on this exercise? What are the instructions? What are you trying to do? How far have you gotten?

Eliz.
 
3(x+y)=-2y-7
assume that you need to rearrange and solve for y.....

3x+ 3y = 2y-7
3y-2y = -7 - 3x
y =-7 - 3x

your answer looks like you have treated the 3 incorrectly. When the 3 is outside the brackets as shown is is attached to a multiply sign. Your solution has treated this as a plus sign.

all the best.............
 
Hello, afreemanny!

I have tried this problem so many times, and can't get it
. . . really? .Where exactly is your difficulty?
Click to expand...
3(x + y) .= .-2y - 7 . . → . . 3x + 5y .= .-7
. . . .-3y .= .10 - 4x . . → . . 4x - 3y .= .10 . . . etc.
 
A good first step would be to multiply out the first equation, to get rid of the parentheses. Then rearrange both equations to get the x- and y-terms together on one side, with the loose numbers on the other side.

How far have you gotten in this process? Please reply showing what you've tried thus far. Thank you.

Eliz.
 
Eliz

This is what I have done....not right though, and not sure where I am wrong.

3(x+y)=-2y-7----------3x+5y=-7
-3y=10-4x -----------4x-3y=10

12 is the LCM of 3 and 4

12x+20y=-28
-12x-9y=30
____________
11y=-58

I stoped there because I know it is wrong...not sure where though. :cry:
Thanks so much Eliz.
Amy
 
Re: Eliz

afreemanny said:
4x-3y=10

12 is the LCM of 3 and 4

-12x-9y=30
Click to expand...
How did you multiply the second equation through by -3 and yet change the sign on only one of the equation's three terms?

Eliz.
 
HI

I don't know what I am doing wrong with this.....can you tell me what I am doing wrong please???? Thanks someone.
 
Re: HI

afreemanny said:
can you tell me what I am doing wrong please?
Click to expand...
As mentioned in my previous post, you're multiplying incorrectly. Check your signs when you multiply -3 through the second equation.

Eliz.
 
You must log in or register to reply here.
Top