D =
IR : (a-b)² = a²-2ab+b²
On applique ...
(8x-5)²
= (8x)²-2*8x*5+5²
= 64x²-80x+25
E = IR : (a-b)(a+b) = a²-b²
On applique :
E = - (10x+6) (10x-6)
E = -[(10x)²-6²]
E = -[100x²-36]
E = -100x²+36
F : IR = (a-b)² = a²-2ab+b²
On applique :
1/25x²-2/45x+1/81
IR = Identité Remarquable
