Помогите. Можно по подробней плиз, не понимаю немного.

1) 4a – (5a – (a – 2/9)), если a=0,37;
2/9=0,222222
a – 2/9 = 0,37 - 0,222222 = 0,147778
5a = 5*0,37 = 1,85
5a – (a – 2/9) = 1,85 - 0,147778 = 1,702222
4a = 4*0,37 = 1,48
4a – (5a – (a – 2/9)) = 1,48 - 1,702222 = -0,22222

2) 6x – 4*(3y – 5x) + 3*(2y – 5x + 1), если x=3/11, y= – 5/6;
x=3/11 = 0,272727
y= – 5/6 = - 0,833333
6x = 6*0,272727 = 1,636364
3y = 3*- 0,833333 = - 2,5
5x = 5*0,272727= 1,363636
2y = 2 *( - 0,833333) = - 1,666667
2y – 5x + 1 = - 1,666667 - 1,363636 + 1 = -2,0303
3*(2y – 5x + 1) = 3*(-2,0303) = -6,09091
3y – 5x = - 2,5 - 1,363636 = -3,86364
4*(3y – 5x) = -3,86364
4*(-3,86364) = -15,4545
6x – 4*(3y – 5x) = 1,636364 – (-15,4545) = 17,09091
6x – 4*(3y – 5x) + 3*(2y – 5x + 1) = 17,09091 +(-6,09091) = 11

3) 12m – 5*(2n – (n – (1 – 5n))), если 3m + 4n= – 2.
3m + 4n= – 2
3m = - 4n – 2
12m = 4*(- 4n – 2)
4*(- 4n – 2) – 5*(2n – (n – (1 – 5n)))
- 16n – 8 – 10 n – (5n – (5-25n)) - дальше сам.

(2/9, 3/11, 5/6 дроби)