Question

(3m – 9) -- (-10m – 9)

Answer 1

the answer is 13m

Explanation:

remove parenthesis : 3m – 9 + 10m – 9

simplify : 3m - 9 +10 +9 = 13m

Answer 2

-13m - 18

Explanation:

(3m - 9) -- (-10m - 9 )

Subtract the 3m to the -10m, and add the 9's together.