Question

Reduce:
C = (x + 5)(x - 5) - (x + 7)(x - 7)​

Answer 1

Respuesta:     $C=24$

Pasos:

$C=\left(x+5\right)\left(x-5\right)-\left(x+7\right)\left(x-7\right)$

$\mathrm{Desarrollar\:}\left(x+5\right)\left(x-5\right)-\left(x+7\right)\left(x-7\right)$

$\mathrm{Expandir}\:\left(x+5\right)\left(x-5\right):\quad x^2-25$

Queda:

$=x^2-25-\left(x+7\right)\left(x-7\right)$

$\mathrm{Expandir}\:-\left(x+7\right)\left(x-7\right):\quad -x^2+49$

Queda:

$=x^2-25-x^2+49$

$\mathrm{Simplificar}\:x^2-25-x^2+49:\quad 24$

Queda:

$=24$

Finalmente:

$C=24$