Question

solve for u.
2u + 9 = 8u + 21
simplify your answer as much as possible.

Explanation:

Step1: Subtract $2u$ from both sides

$2u + 9 - 2u = 8u + 21 - 2u$
$9 = 6u + 21$

Step2: Subtract 21 from both sides

$9 - 21 = 6u + 21 - 21$
$-12 = 6u$

Step3: Divide by 6 on both sides

$\frac{-12}{6} = \frac{6u}{6}$
$u = -2$

Answer:

$u = -2$