Răspuns:
Baftă...
Explicație pas cu pas:
a)(x+20):12+68=78
(x+20):12=78-68
(x+20):12=10
x+20=10×12
x+20=120
x=120-20
x=100
b) (x+282-75):2=104
x+207=104×2
x+207=208
x=208-207
x=1
c)x×4:10+101=133
x×4:10=133-101
x×4:10=32
x×4=32×10
x×4=320
x=320:4
x=80