CORRECTION 2) Factoriser en trouvant un facteur commun :
Factoriser les expressions suivantes :
W(x) = 15 x + 35 A(x) = 2 x2– 3 x
= 5(3 x+7) = x(2 x−3)
B(x) = 14 x6– 8 x5
= 2 x5×7 x−2 x5×4
= 2 x5(7 x−4)
C(x) = x23 x4x2– 5 x1
= (x+2)[(3 x+4)+(−5 x+1) ]
= (x+2)(3 x+4−5 x+1)
= (x+2)(−2 x+5) D(x) = x – 63 x – 4–x – 6
= (x−6) [(3 x−4)−1]
= (x−6)(3 x−5)
E(x) = x – 23 x42 – x5 x8
= (x−2)(3 x+4)−(x−2)(5 x+8)
= (x−2)[(3 x+4)−(5 x+8)]
= (x−2)(3 x+4−5 x−8)
= (x−2)(−2 x−4)
F(x) = 2 x – 143 x – 4–3 x – 21x4
= 2(x−7)(3 x−4)−3(x−7)(x+4)
= (x−7)[2(3 x−4)−3(x+4)]
= (x−7)(6 x−8−3 x−12)
= (x−7)(3 x−20)