Sagot :
*= multiplication
(2x+1)(x-4) = x(2x-4)
2x*x + 2x*(-4) + 1*x + 1*(-4) = x*2x + x*(-4)
2x² - 8x + x - 4 = 2x² -4x
2x² - 9x - 4 = 2x² - 4x
2x² - 9x -2x² + 4x = 4
-5x = 4
(2x+1)(x-4)=x(2x-4)
(2x+1)(x-4)-x(2x-4) = 0
2x²-8x+x-4 -2x²+4x = 0
-3x - 4 = 0
-3x= 4
x= -4/3
(1/3x+2)(-2x+3)=0
(x+1/6)(-2x+3)=0
x= 3/2 ou x = -1/6
16x²=25
x² = 25/16
x = 5/4 ou x = -5/4
(3x-8)(x-2)-(x-2)(3+x)=0
(x-2)(3x-8-3-x) = 0
(x-2)(2x-11) = 0
x = 2 ou x = 11/2
8x²-4x^3=0
4x(x-2) = 0
x = 0 ou x = 2
(x+4)²=12x+12
(x+4)²-12x-12 = 0
x²+8x+16 - 12x - 12 = 0
x² -4x 4 = 0
(x-2)² = 0
x=2
En espérant t'avoir aidé .