Răspuns:
b este raspuns corect .
[(X+15)•10-100]:5+90=100
[(x+15)•10-100]:5=100-90
[(x+15)•10-100]=10•5
(x+15)•10=50+100
(x+15)=150:10
x+15=15
x=15-15
x=0
proba[(0+15)•10-100]:5+90=100
(15•10-100):5+90=100
50:5+90=100
10+90=100
100=100
