AYA937
Answered

Aider moi SVP
1) Developper et reduire

a) (5x+7)(1-3x)
b) 4x(-x+3) - (2x+5) (x-1)
c) (y+1/5) (y-1/5)

(vous pouvez mettres tout les etapes svp)

Sagot :

DROOPETTE
a) (5x+7)(1-3x)
=5x-15x²+7-21x
=-15x²-16x+7

b) 4x(-x+3) - (2x+5) (x-1)
=-4x²+12x-(2x²-2x+5x-5)
=-4x²+12x-2x²+2x-5x+5
=-6x²+9x+5
c) (y+1/5) (y-1/5)
=y²-(1/5)²
=y²-1/25 car (a+b)(a-b)=a²-b²

d)(4x-7)²= 16x²-56x+49