3x - 21 = 2y

Question

3y = 84 - 6x

Using the two equations above, solve for y.

A.11
B.35
C.-6
D.6

Answer 1

3 y = 84 - 6 x Divide both sides by 3

y = 28 - 2 x

3 x - 21 = 2 y

3 x - 21 = 2 ( 28 - 2 x )

3 x - 21 = 56 - 4 x

3 x + 4 x = 56 + 21

7 x = 77 Divide both sides by 7

x = 77 / 7

x = 11

y = 28 - 2 x

y = 28 - 2 * 11

y = 28 - 22

y = 6

D.6