exo 7
A=-(-8x+8)(6x-6)+64-128x+64x²
A=-(-48x²+48x+48x-48)+64-128x+64x²
A=48x²-96x+48+64-128x+64x²
A=112x²-224x+112
A=-48(-x+1)(x-1) +8²-2*8*8+(8x)²
A=-48(1-x)(x-1)+(8-8x)²
A=-48(1-x)(x-1)+64(1-x)²
A=16(1-x)[-3(x-1)+4(1-x)]
A=16(1-x)(-3x+3+4-4x)
A=16(1-x)(-7x+7)
A=112(1-x)²
si x=-2, alors A=112*(1+2)²=112*9=1008
A=0 ⇔ 112(1-x)²=0 ⇔1-x=0 ⇔ x=1
exo8
A= -(3x+5)(2x+10)-(3x+3)(3x+5)
A= -(6x²+30x+10x+50)-(9x²+15x+9x+15)
A= -(6x²+40x+50)-(9x²+24x+15)
A= -6x²-40x-50-9x²-24x-15
A= -15x²-64x-65
A= -(3x+5)(2x+10)-(3x+3)(3x+5)
A= -2(3x+5)(x+5)-3(x+1)(3x+5)
A= -(3x+5)[2(x+5)+3(x+1)]
A= -(3x+5)(2x+10+3x+3)
A= -(3x+5)(5x+13)
pour x=-7/8 alors A= -(-3*7/8+5)(-5*7/8+13)
A= - (-21/8+5)(-35/8+13)
A= -(-21/8+40/8)(-35/8+104/8)
A= -(19/8)*(69/8)
A= -1311/8
A=0 ⇔3x+5=0 ou 5x+13=0
⇔x= -5/3 ou x= -13/5
exo9
A=-(5x-1)(6x-9)+(5x-1)²
A= -(30x²-45x-6x+9)+(25x²-10x+1)
A=-30x²+51x-9+25x²-10x+1
A= -5x²+41x-8
A=(5x-1)[-(6x-9)+(5x-1)]
A=(5x-1)(-6x+9+5x-1)
A=(5x-1)(-x+8)
pour x=-9/10, A=(-5*9/10-1)(9/10+8)
A=(-45/10-10/10)(9/10+80/10)
A=(-55/10)(89/10)
A=(-55*89)/10
A=-4895/10
A=0 ⇔ 5x-1=0 ou -x+8=0
⇔x=1/5 ou x=8
exo10
A=(4x+3)²-(-x+10)(4x+3)
A=16x²+24x+9-(-4x²-3x+40x+30)
A=16x²+24x+9+4x²-37x-30
A=20x²-13x-21
A=(4x+3)[(4x+3)-(-x+10)]
A=(4x+3)(4x+3+x-10)
A=(4x+3)(5x-7)
si x=-3/2 alors A=20*(-3/2)²+13*3/2-21
A=20*9/4+39/2-21
A=(180+78-21*4)/4
A=174/4
A=87/2
A=0 ⇔4x+3=0 ou 5x-7=0
⇔x=-3/4 ou x=7/5
