Question 762178
 7a-{(2ab+b-5)-[(-3a+5ab-1)+(3a+2b-ab)]}
 7a-{2ab + b - 5 + 3a - 5ab + 1 + 3a + 2b - ab}
 7a-{6a + 3b - 4ab -4}
 7a - 6a - 3b + 4ab + 4
   -a - 3b + 4ab + 4