Question

Ayuda plis:
3) Resolver:
$\frac{(x+4)^{2}-(x+5)(x+3)-1 }{(x+2)(x-2)-(x+1)(x-1)}$
A) 1 B) 2 C) – 1 D) 0 E) – 2

4)Si: $x-x^{-1} =5$
Calcular:$x^{3} -x^{-3}$
A) 140 B) 110 C) 80 D) 120 E) 90

Answer 1

PROBLEMA 3

$\frac{(x+4)^{2}-(x+5)(x+3)-1 }{(x+2)(x-2)-(x+1)(x-1)} \\ \frac{ {x}^{2} + 16 + 8x - {x}^{2} - 8x - 15 - 1 }{ {x}^{2} - 4 - {x}^{2} + 1 } \\ \frac{0}{ - 3} \\ 0$

PROBLEMA 4

$x-x^{-1} =5 \\ x - \frac{1}{x} = 5$

$(x - \frac{1}{x} ) {}^{3} = {5}^{3} \\ {x}^{3} - \frac{1}{ {x}^{3} } - 3(x)( \frac{1}{x} )(x - \frac{1}{x}) = 125 \\ {x}^{3} - \frac{1}{ {x}^{3} } - 3(5) = 125 \\ {x}^{3} - \frac{1}{ {x}^{3} } - 15 = 125 \\ {x}^{3} - \frac{1}{ {x}^{3} } = 125 + 15 \\ {x}^{3} - \frac{1}{ {x}^{3} } = 140$