Question

15 (y-4)-2 (y-a)+5 (y+6)=0

Answer 1

15y-60-2y+2a+5y+30=0

18y-30-2a=0

Divide eqn by 2

9y-15-a=0

9y-a=15

if we need to find y then

y=15+a/9

if we need to find a then

-a=15-9y

a=9y-15