Q:

Use the drop-down menus to choose steps in order to correctly solve 5(z + 6) – 2 = 9z for z.

Accepted Solution

A:
Solve for z:
5 (z + 6) - 2 = 9 z

5 (z + 6) = 5 z + 30:
5 z + 30 - 2 = 9 z

Add like terms. 30 - 2 = 28:
5 z + 28 = 9 z

Subtract 9 z from both sides:
(5 z - 9 z) + 28 = 9 z - 9 z

5 z - 9 z = -4 z:
-4 z + 28 = 9 z - 9 z

9 z - 9 z = 0:
28 - 4 z = 0

Subtract 28 from both sides:
(28 - 28) - 4 z = -28

28 - 28 = 0:
-4 z = -28

Divide both sides of -4 z = -28 by -4:
(-4 z)/(-4) = (-28)/(-4)

(-4)/(-4) = 1:
z = (-28)/(-4)

The gcd of 28 and -4 is 4, so (-28)/(-4) = (-(4Γ—7))/(4 (-1)) = 4/4Γ—(-7)/(-1) = (-7)/(-1):
z = (-7)/(-1)

(-7)/(-1) = (-1)/(-1)Γ—7 = 7:
Answer:Β  z = 7