Question

What does a equal -5(6a+21)=-15

Answer 1

Step 1 remove paranthesis
(-30a-105)=-15

Step 2: Move constant to RHS (take not negative sign is removed if sides are changed and vice versa)

-30a=-15+105
-30a=90

Step 3: Simplify
-a=3

Step 4: remove negative sign from variable
a=3