Question

Descompuneti in factori :
${x}^{3} + {2x}^{2} - 16(x + 2) =$
$16 {(x + 5)}^{2} - 9 {(2x - 3)}^{2} =$

Answer 1

x^3 + 2x^2 - 16(x + 2) =
x^2(x + 2) - 16(x + 2) =
(x + 2)(x^2 - 16) =
(x + 2)(x - 4)(x + 4) 

16 (x + 5)^2 - 9(2x - 3)^2 = 
4^2(x + 5)^2 - 3^2(2x - 3)^2 = 
(4(x+5) + 3(2x-3))(4(x + 5) - 3(2x - 3)) = 
(4x + 20 + 6x - 9)(4x + 20 - 6x + 9) =
(10x + 11)(- 2x + 29)