Question 284387
6* { [3*(c-4)+19] - [3*(2c-3)+1] }
break it up
....3*(c-4)=3c-12

....3*(2c-3)=6c-9

6* { [3c-12+19] - [6c-9+1] }
..........- [6c-9+1]=-(6c-8)=-6c+8
6*(3c+7-6c+8)=
6*(-3c+15)=
-18c+90=
90-18c