() × 1 / 8 = 0.2 × () = (): 2 / 3 = 1

() × 1 / 8 = 0.2 × () = (): 2 / 3 = 1

(8) × 1 / 8 = 0.2 × (5) = (2 / 3): 2 / 3 = 1

10×(2-X)-9×(2-X)-7×(2-X)=56

Let's take 2-x as a number,
10×(2-X)-9×(2-X)-7×(2-X)=56
(2-X)(10-9-7)=56
(2-X)(-6)=56
-12+6X=56
6X=68
X=34/3

(1) X: 3 = 0.75:1 in 10 (2) 7:8 = x: 56 (3) x: 1 in 3 = 1 in 15:
(1) X: 3 = 0.75: (2) 7: 8 = x: 56 (3) 1 / 3 of x = 1 / 15 of X: 1 / 3

(1) X: 3 = 0.75:10 (1 / 10) x = 2.25 x = 22.5 (2) 7:8 = x: 56 8x = 7 * 7 * 8 x = 49 (3) x: 1:3 = 15:1:5 (1 / 5x) = 1 / 45 5x = 45 x = 9

（X+35\8)*2=10.25 3.14*x=8=20.56

（X+35\8)*2=10.25
X+35/8=41/8
X=3/4
3.14*x+8=20.56
3.14x=12.56
x=4