2) Factoriser si possible:
P1(x)= -24x² +2x+35
=(4x-5)(-6x-7)
P2(x)= x²-25
=(x-5)(x+5)
P3(x)= 9x²-30x+25
=(3x-5)²
P4(x)= 20x²-40x+53
=non factorisable dans IR
P5(x)= -x²-6x+7
=(-x+1)(x+7)
P6(x)= x²+8
=non factorisable dans IR
P7(x)= 2x²+5x-3
=(x+3)(2x-1)