1) 1,2a-8=0,4a 2) - x-1,4=0,4x 3) 0,6y+4=0,2y 4) 2-3,5a=1,5a

Найдем корни уравнений.

1) 1,2 * a - 8 = 0,4 * a;

Приведем к виду a * x = b.

1,2 * a - 0.4 * a = 8;

a * (1.2 - 0.4) = 8;

a * 0.8 = 8;

a = 8/0.8;

a = 80/8;

a = 10.

2) - x - 1,4 = 0,4 * x;

-x - 0.4 * x = 1.4;

x * (-1 - 0.4) = 1.4;

x * (-1.4) = 1.4;

x = - 1.4/1.4;

x = - 1.

3) 0,6 * y + 4 = 0,2 * y;

0.6 * y - 0.2 * y = - 4;

y * (0.6 - 0.2) = - 4;

y * 0.4 = - 4;

y = - 4/0.4;

y = - 40/4;

y = - 10.

4) 2 - 3,5 * a = 1,5 * a;

2 = 1.5 * a + 3.5 * a;

a * (1.5 + 3.5) = 2;

a * 5 = 2;

a = 2/5;

a = 0.4.