Решите уравнение: а) 1/2 (4- 3целых1/2x)=1целая1/4х- 1/2 б) 0.2 (5у-2)=0.3(2у-1)-0.9 в) 4(1-0.5а)=-2(3+2а)

A.

1/2(4-3 1/2x) = 1 1/4x - 1/2

2-7/4x = 5/4x-1/2

2+1/2 = (7/4+5/4)x

12/4x = 2 1/2

3x = 2 1/2

x = 5/2 : 3 = 5/6

B.

0.2(5y - 2) = 0.3(2y-1)-0.9

y-0.4 = 0.6y-0.3-0.9

y-0.6y = -1.2 + 0.4

0.4y = -0.8

y = -2

C.

4(1-0.5a) = -2(3+2a)

4-2a = -6-4a

-2a+4a = -6-4

2a = -10

a=-5