Question

Solve the system using substitution 3x+2y=-14 and y=x+3

Answer 1

3x-2y=14
x-y=-3

3x-2y=-14
(-2)(x-y=-3)

3x-2y=-14
-2x+2y=6

x=-8
Then plug in x to one of the equations

Answer 2

3x + 2y = -14
y = x + 3

Substitution means you solve one equation for one unknown and substitute it into the other equation. In this case, the second equation is already solved for y. To substitute, substitute y in the first equation by x + 3.

3x + 2(x + 3) = -14
Now we solve this equation for x:
3x + 2x + 6 = -14
5x = -20
x = -4

Now that we know x, we substitute x into one of the two original equations to find y. Let's use the second equation:

y = -4 + 3
y = -1

The solution is: x = -4, y = -1

Answer 3

oops lol i didny do substitution.. good job @mathstudent55

Answer 4

@Daniellee
The answers should be the same no matter which method you use. You tried to solve the system by addition, but you inadvertently changed the first equation to a different equation. That's why your answer is incorrect.
y = x + 3 is the same as x - y = -3
3x + 2y = -14 is not the same as 3x - 2y = 14