Bonsoir,

20 -4x = 0

20 = 4x

x= 20/4

x = 5

3x+3 =4x-2

3+2 = 4x-3x

5 = x

x= 5

x² +1 = -x 65

x² +x = 65 -1

x²+x = 64

13 = 10-x

x= 10 -13

x= -3

(x+3) * 2 = 2x+6

2x+6 = 2x+6

2x-2x = 6-6

0=0

x= 0

x²-1 = 10x -22

x² -10x = -22+1

x²-10x = -21