Réponse :
Développer :
a) (a+b)^2 = a^2+2ab+b^2
x^2+ 2*x*5+5^2
= 2x+ 2x+5 +25
b) (a-b)^2 = a^2-2ab+b^2
8^2-2*8*3x^2
64-16-6x^2
c) (a+b)(a-b) = a^2-b^2
2x^2-6/11^2
4x^2- 36/121
Factoriser :
a^2+2ab+b^2 = (a-b)^2
a) 16x^2 +49
= 4^2+7^2
= (4x-7)(4x-7)
a^2-2ab+b^2 = (a-b)^2
b) y^2-10y+25
= (y)^2-10y+5^2
= (y-5)^2
c) a^2+2ab+b^2 = (a-b)^2
9x^2+15x+ 25/4
(3x)^2+15x+ 5^2/ 2^2
(3x-5/2)^2