Question

120:(g-15) =9.........

Answer 1

120:(g-15)=9
g-15=120*9
g-15=1080
g=1080+15
g=1095
120:(1095-15)=9
9=9

Answer 2

$120:(g-15)=9;\\g-15=120:9;\\g-15=\frac{120}{9} ;\\g-15=\frac{40}{3} ;\\g=\frac{40}{3} +15;\\g=\frac{40+45}{3} =\frac{85}{3} =28\frac{1}{3}$