Question

For the following system, use the second equation to make a substitution for y in the first equation. 3x + y = 2 y + 4 = 3x

Answer 1

First, set the second equation with y as the isolated variable. To do this, subtract 4 from both sides to get
$y = 3x - 4$
Now that you know the value of y, put that expression in for y in the first equation to get
$3x + (3x - 4) = 2$
Then, simplify by adding the x terms together to get
$6x - 4 = 2$
add 4 on both sides to isolate the x terms to get
$6x = 6$

then divide 6 from both sides to get
$x = 1$
Using that x value, plug it into one of the equations as x to find y ( I will use y=3x-4)
$y = 3(1) - 4 = 3 - 4 = - 1$
x=1 and y=-1 is the answer