Question

A=a+b+c / over 3
solve for b
A.) 3A - a - c = b
B.) -c / 3 = b
C.) A - c / 3 = b
D.) -3 - c = b

Answer 1

First get rid of the denominator by multiplying both side by 3. Then solve for b by moving a and c to the other side leaving b alone.

Answer 2

A(3) = (a+b+c)/3 * 3
3A = a+b+c
3A-a-c = a+b+c-a-c
3A-a-c = b
b= 3A-a-c