Salut !

Ex. 1 :

x+ 15 = 25 donc x = 25 - 15 = 10

9x = 72 donc x = 72/9 = 8

3x + 5 = 32 donc 3x = 32 - 5 = 27 donc x = 27/3 = 9

6x - 2 = 7 donc 6x = 7 + 2 = 9 donc x = 9/6 = 3/2

4x + 3 = 2x - 9 donc 4x - 2x = -9 - 3 donc 2x = -12 donc x = -12/2 = -6

9x + 4 = 5x - 2 donc 9x - 5x = -2 - 4 donc 4x = -6 donc x = -6/4 = -3/2

Ex. 2 :

A = -5(3x+2) = -15x + 10

B = (2x-3)(6x+5) = 12x²+10x-18x-15 = 12x²-8x-15

Ex. 3 :

A = 4x+ 4y = 4(x+y)

B = 3x²-2x = x(3x-2)

C = 3(x+2)+5(x+2) = (3+5)(x+2) = 8(x+2)

D = (x+3)(x-5)+(x+3)(2x+4) = (x+3)[(x-5)+(2x+4)] = (x+3)(3x-1)