Sagot :
bjr
3ème cas :
il y a plusieurs facteurs communs
K= 5x²+ 10x = 5×x×x +5×2×x = 5×x×(x + 2) = 5x(x +2)
L = 18b –27b² = 9×2×b.–9×3×b×b= 9×b×(2– 3×b) = 9b (2 – 3b)
4èmecas : Le facteur commun est une expression littérale
M= (x+ 2)(3x+ 1) + (x+ 2)(2x–4)= (x + 2)×(3x + 1) + (x + 2)×(2x – 4)
M= (x+ 2) × [(3x + 1) +(2x - 4)] = (x+ 2) × [3x + 1 + 2x – 4] = (x+ 2)(5x - 3)
N= (2a –5)² –(2a –5)(a + 3) = (2a –5)×(2a – 5)–(2a –5)×(a +3)
N = (2a–5) × [(2a - 5)–(a + 3)] = (2a–5) × [2a – 5 – a – 3)] = (2a–5)(a – 8)