Решите уравнение : a) 3,5x - 2,3x + 3,8 = 4,28; б) 4,7y - ( 2,5y + 12, 4) = 1,9; в ) ( 8,3 - r ) × 4,7 = 5,64; г) (9,2 - m ) × 3,2 = 16.

3.5x - 2.3x + 3.8 = 4.28
1.2x + 3.8 = 4.28
1.2x = 4.28 - 3.8
1.2x = 0.48
x = 0.48/1.2
x = 0.4 

4.7y - (2.5y + 12.4) = 1.9
4.7y - 2.5y - 12.4 = 1.9
2.2y = 1.9 + 12.4
2.2y = 14.3
y = 14.3/2.2
y = 6.5

(8.3 - r) * 4.7 = 5.64
8.3 - r = 5.64 / 4.7
8.3 - r = 1.2
r = 8.3 - 1.2
r = 7.1

(9.2 - m) * 3.2 = 16
9.2 - m = 16 / 3.2
9.2 - m = 5
m = 9.2 - 5
m = 4.2