a)7/18+x=19/15
x=19/15-7/18
x=19*6-7*5)/90
x=(114-35)/90
x=79/90
b)9*x=12
x=12/9=4/3
c) x*4/25=16/5
4x/25=(16*5)/25
4x=16*5
x=20
d) (35/24):4=2,(3)
2,(3)=(23-2)/9
unde este necunoscuta?
e) 4x+5=x+13
4x-x=13-5
3x=8
x=8/3
f)11x+17=2x+21
11x-2x=21-17
9x=4
x=4/9
