Answer: 7.29 or 7 1/4 or 29/4 (they're all equal, just rewritten)
Explanation:
the angles are equal, so we set the equations to each other and then solve. here's my work:
12k - 9 = 8k + 20
12k (- 8k) - 9 = 8k ( - 8k) + 20
4k - 9 = 20
4k -9 ( + 9) = 20 ( + 9)
4k = 29
k = 7.29 or 7 1/4 or 29/4