a)
la + b = 42
2a + 18b = 420
d)
25p - 49 = R
12p + 68 = R
la- b = 43
b)
| 125a + 8b = -110
x + y = 2
e
5x + 80y = 130
c)
5(x + y) = 40
(21x - 3y = -35
f)
5s - 77 = 18,9
S+ 4+ = -8,1
пожалуйста помогите​