factoriser et reuire les facteurs (y+2)(5y-7)+(y+2)(2y+9) //4-12t+9t2 //4xau carré+28x+49

bonjour,

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

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

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

Bonjour , 
1/ (y+2)(5y-7)+(y+2)(2y+9)
= (y+2) [(5y-7)+(2y+9)]
= (y+2) (7y+2)
2/ 4 - 12t + 9t²
= 2² - 2 × 3t × 2 + (3t)²
= (2-3t)²
3/ 4x² + 28x + 49 
= (2x)² + 2 × 2x × 7 + 7²
= (2x+7)²