I have tried to help one of my friends with this problem but the answer key has a different answer than mine...did i do something wrong?

So the problem asks to solve each system using substituition or eliminitation:

I chose substituion.

3x+5y=-3

x+2y= -4/3

1) i tried to isolate the x and i got the equation x=-2y-4/3

2) i plugged the value of x in to the first equation and got y=7

and that is where i went wrong...can somebody explain my mistake to me. Thanks.

Nirvana Sep 14, 2019

#1**+2 **

Solve the following system:

{3 x + 5 y = -3 | (equation 1)

x + 2 y = -4/3 | (equation 2)

Subtract 1/3 × (equation 1) from equation 2:

{3 x + 5 y = -3 | (equation 1)

0 x+y/3 = (-1)/3 | (equation 2)

Multiply equation 2 by 3:

{3 x + 5 y = -3 | (equation 1)

0 x+y = -1 | (equation 2)

Subtract 5 × (equation 2) from equation 1:

{3 x+0 y = 2 | (equation 1)

0 x+y = -1 | (equation 2)

Divide equation 1 by 3:

{x+0 y = 2/3 | (equation 1)

0 x+y = -1 | (equation 2)

Collect results:

**x = 2/3 and y = -1**

Guest Sep 14, 2019