Verified answer

1) (y:4-35)*12=300

y:4-35= 25

y:4=60

y=240

2) (150:y+6)-6=50

150:y+6=56

150:y=50

150:50=y

y=3

3) (8x-30):2=225

8x-30=450

8x=480

x=60