Bonjour,
identités remarquables......
a²-b² = (a+b)(a-b)
donc : (x-3)²-100 = (x-3)²-10² = (x-3+10)(x-3-10) = (x+7)(x-13
(a+b)² = a²+2ab+b²
donc : 49x²+56x+16 = (7x)²+2(7x)(4)+4² = (7x+4)²
(a-b)² = a²-2ab+b²
donc : x²-2x+1 = x²-2(x)(1)+1² = (x-1)²
8x - 64 = 8(x-8)
(4x+5)-(4x+5)² = 1(4x+5)-(4x+5)(4x+5)
= (4x+5)(1-4x+5)
= (4x+5)(4-4x)
