Question

ayúdenme porfavor. Calcular E=
$(x + 4)(4 - x) + ( \sqrt{ \times } + 1)( \sqrt{x} - 1)(x + 1)$
​

Answer 1

Solo recuerda que:

${x}^{2} - {y}^{2} = (x + y)(x - y)$

...

$E = (4 + x)(4 - x) + ( \sqrt{x} + 1)( \sqrt{x} - 1)(x + 1) \\ E = 16 - {x}^{2} + ( (\sqrt{x}) {}^{2} - 1)(x + 1) \\ E = 16 - {x}^{2} + (x - 1)( x + 1) \\ E = 16 - {x}^{2} + {x}^{2} - 1 \\ E = 15$