7x+5 = 4x-5
7x-4x = -5-5
3x = -10
x = -10/3
x = -3 1/3 (минус 3 целых 1 третья)
4(3x-2) = 5x+9
4*3x-4*2 = 5x+9
12x-8 = 5x+9
12x-5x = 9+8
7x = 17
x = 17/7
x = 2 3/7 (2 целых 3 седьмых)
x-5(3x-5) = -10x+2
x-5*3x+5*5 = -10x+2
x-15x+25 = -10x+2
-14x+10x = 2-25
-4x = -23
4x = 23
x = 23/4
x = 5,75