bonsoir

(2x+1)(x-3)+(2x+1)(3x+2)

2x²-6x+x-3+6x²+4x+3x+2

8x²+2x-1

b/

(2x+1)(x-3)+(2x+1)(3x+2)

(2x+1)(x-3+3x+2)

(2x+1)(4x-1)

3/

a)

f(0) = 8x²+2x-1= 8(0)²+2(0) -1 =0+0-1 = 0

f(-1/2) = (2x+1)(4x-1) =(2*-1/2 +1)(4*-1/2-1)=(-1+1)(-2-1) =(0)(-3) =0

f(V2) = 8x²+2x-1= 8(V2)² +2(V2) -1 =8(2) +2V2 -1 =16+2V2 -1 = 2V2+15

b)

(2x+1)(4x-1) =0

2x+1 = 0       4x-1 =0

2x = -1            4x =1

x = -1/2             x = 1/4

c)

-1/2 et 1/4

d)

8x²+2x-1 = 8x²

8x²+2x-1-8x² =0

2x-1 =0

2x =1

x =1/2