Question

X = 3 - y

5x - 12 = y
Using the two equations above, solve for y.
A. y = 0.5
B. y = 2.5
C. y = -2
D. y = 5.5

Answer 1

A

Explanation:

Plug the first equation into the second equation. 5(3-y)-12=y

15-5y-12=y. Combine like terms. 3-5y=y. Move the -5y to the other side. 3=y+5y which is 3=6y divide and y=1/2 or 0.5

Answer 2

A

Explanation:

Given the 2 equations

x = 3 - y → (1)

5x - 12 = y → (2)

Substitute x = 3 - y into (2)

5(3 - y) - 12 = y ← distribute and simplify left side

15 - 5y - 12 = y

3 - 5y = y ( add 5y to both sides )

3 = 6y ( divide both sides by 6 )

`(3)/(6)` = y, that is

y = 0.5 → A