A=( 5x+2)(5x+2)+ (5x+2)(3x-4)
développer et réduire.
A=( 5x+2)(5x+2)+ (5x+2)(3x-4)
=25x²+20x+4+15x²-20x+6x-8
=40x²+6x-4
calculer a pour x= - 1/3
40x²+6x-4
=40(-1/3)²+6(-1/3)-4
=40*1/9-6/3-4
=40/9-2-4
=40/9-6
=40/9-54/9
=-14/9
factoriser A
A=( 5x+2)(5x+2)+ (5x+2)(3x-4)
=( 5x+2)( 5x+2+3x-4)
=( 5x+2)(8x-2)
=2( 5x+2)(4x-1)
