Sagot :

Hello,

2x - 3 = 4 + x

2x - x = 4 + 3

x = 7

y + 4 = - 4 - 3y

y + 3y = - 4 - 4

4y = -8

y = -8/4 = -2

7x - 6 = 4 - 3x

7x + 3x = 4 + 6

10x = 10

x = 10/10 = 1

12 - a = 18 - 3a

- a + 3a = 18 - 12

2a = 6

a = 6/2 = 3.