help w/ solving systems: -x + 4y = 8, 2x - 3y = -16

jazzy2011

New member
Joined
Jun 2, 2008
Messages
1
ok. i have to solve this problem:

-x+4y=8
2x-3y=-16

i know that 1st you have to try to get "y" by itself on one of the sides but after that im confused. this is what i did...

-x+4y=8
+x +x
__________
4y=x+8
--- -----
4 4
y= ?? +2

then for the other side when i tried yto find "y" i did this...

2x-3y=-16
-2x -2x
-3y= -2x-16
----- --------
-3 -3
y= 2/3x+16/3

and for the 2nd one, when i plug it into the other problem it doesn't come out right. so what do i do??
 
Re: help plz!

jazzy2011 said:
ok. i have to solve this problem.

-x+4y=8 2x-3y=-16

i know that 1st you have to try to get "y" by itself on one of the sides but after that im confused. this is what i did...

-x+4y=8
+x +x
__________
4y=x+8
--- -----
4 4
y= ?? +2


then for the other side when i tried yto find "y" i did this...



2x-3y=-16
-2x -2x
-3y= -2x-16
----- --------
-3 -3
y= 2/3x+16/3

and for the 2nd one, when i plug it into the other problem it doesn't come out right. so what do i do??

For a quick review - go to:

http://www.purplemath.com/modules/systlin4.htm
 
Re: help plz!

y= ?? +2

That's \(\displaystyle y=\frac{x}{4}+ 2\). See why?

Now, in place of y in the other equation, substitute in (x/4)+2, and solve for x. Once you find the value of x, plug that into either of the original equations and solve for y.
 
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