1)6(2x+1)=78
12x+6=78
12x=72
x=6
2)7(3x-3)=70
21x-14=70
21x=84
x=4
3)2(x+5)-7=19
2x-10=26
2x=36
x=18
4)4(3x+2)+15=71
12x+8=56
12x=48
x=4
5)3x+4x=28
7x=28
x=4
6)5x+x-2x=36
4x=36
x=9
7)9x-4x+11=3x-x+44
5x+11=2x+44
5x-2x=44-11
3x=33
x=11
8)3(x+7)+2(x-10)=21
3x+21+2x-20=21
5x+1=21
5x=20
x=4
9)=nu mai stiu cum se face