Question

Y= 3x + 1

y= 2x - 3

When using the method called substitution, the y coordinate of the solution to the system of equations shown above is:
A. 13
B. -13
C. 11
D. -11

Answer 1

The answer is D. -11


-3x+1=2x-3 (solve and you will get x= -4)

Substitute x in one of the equations to solve for x

y= 3(-4) + 1

y= -11

Answer 2

y= -11

Explanation:

After rearranging equation 2, we get x= y+3/2

Sub it into equation 1

y= 3(y+3/2) + 1

y= 3y+9/2 + 1

y= 3y + 11 / 2

2y = 3y + 11

-y = 11

y = -11