Question

What is the value of y in the following system y= 3x-5 6x+3y=15

Answer 1

If you plug in (3x-5) in for y in the 6x+3y=15, you will get 6x+9x-15=15. Add the like terms (6x+9x) and get 15x. Bring the -15=15 down. Add 15 to the other 15 on the other side of the equal sign, bring 15x down and then divide 15 by 30 and get x=2. Plug in 2 for x in the (3x-5) equation, then solve and the answer will be 1.

Answer 2

x=2. You use substitution to put the y=3x-5 into 6x+3y=15.
So you get 6x+3(3x-5)=15
=6x+9x-15=15
add 15 on both sides to get the x's alone and add the x's together.
6+9=15 -- 15+15=30
15x=30
30/15 =2
x=2