Answer:
68
Step-by-step explanation:
M
I
L
K
36
AB + BC = AC
4m - 15 + 5m - 6 = 15
m - 21 = 15
m = 36
The correct answer is B- 21b+7bc
7b(3+c)
(7b)(3+c)
(7b)(3)+(7b)(c)
21b+7bc