Solve the equation 3(-a-3)-2(3a+3)=-78

Given equation is 3(-a-3)-2(3a+3)=-78

we can start by distributing numbers which are outside parenthesis

3(-a-3)-2(3a+3)=-78

-3a-9-6a-6=-78

combine like terms

-9a-15=-78

-9a=-78+15

-9a=-63

a=-63/-9

a=7

Hence final answer is a=7.

  or  

step-by-step explanation:

if the four friends split the cost, p, of the pizza evenly, then each friend pays one-fourth of the cost of the pizza.

the expression is   or