Question

what is the answer of this problem:-3(a+3b)+(-1)(a+3b)-7+3(3a+b)

Answer 1

Are you simplifying the expression
-3(a+3b)+(-1)(a+3b)-7+3(3a+b) ?
then
= -3a - 9b - a - 3b - 7 + 9a + 3b
= 5a - 9b - 7