bonjour helpppppppp svp c'est l exo numero 1 merci

bonjour,

x²(3x+9+x+1) =
x²(4x+10)

(y+2)(5y-7+2y+9) =
(y+2)(7y+2)

9t²-12t+4  =a²-2ab+b² = (a-b)²=
(3t-2)²

4x²+28x+49 = a²+2²b+b² =(a+b)²=
(2x+7)²

4y²-100  =a²-b² =(a-b)(a+b) =
(2y-10)(2y+10)

x²-4  =(x-2)(x+2)
(x+2)(x-2+3x+1)=
(x+2)(4x-1)