a)3(7-2x)+14=8x
21-6x+14=8x
21+14=8x+6x
35=14x
35÷14=x
(se simplifica prin 7)
5÷2=x
x=2,5
b)2x=2(8-5x)+12
2x=16-10x+12
2x-12x=16+12
-10x=28
x=28÷(-10)
x=-2,8
c)14x=2(1-5x)+12
14x=2-10x+12
14x+10x=2+12
24x=14
x=24÷14
(se somplifica prin 2)
x=12÷7
x=1,714285(714285)
d)21x=6(3-2x)-42
21x=18-12x-42
21x+12x=18-42
33x=-24
x=24÷33 (si faci calculul)