235 чётныесрочно плиз

2.
1.6*(7х-2) = 4*10.4
11.2х - 3.2 = 41.6
11.2х = 41.6 + 3.2
11.2х = 44.8
х = 44.8 :11.2
х = 4

4.
3.6 * (3х+0.8) = 4.8*9.6
10.8х + 2.88 = 46.08
10.8х = 46.08 - 2.88
10.8х = 43.2
х = 43.2 : 10.8
х = 4

6.
8 * (9х+7) = 28*20
72х + 56 = 560
72х = 560 -56
72х = 504
х = 504:72
х = 7