Question

RESOLVA A EQUAÇÃO;
[ -2 -7 13 ]
[ 0 x -6 ] = 8x + [ 2 0 ]
[ 0 0 x ] [ 11 -5]

Answer 1

$\left|\begin{array}{ccc}-2&-7&13\\0&x&-6\\0&0&x\end{array}\right|=8x+\left|\begin{array}{cc}2&0\\11&-5\end{array}\right|$

$(-2)(x)(x)=8x+(2)(-5)$

$-2x^2=8x-10$

$\boxed{x^2+4x-5=0}$

$\boxed{x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}}$

$x=\dfrac{-4\pm\sqrt{4^2-4(1)(-5)}}{2(1)}=\dfrac{-4\pm6}{2}=-2\pm3$

$\boxed{x=-5}\ \text{ou}\ \boxed{x=+1}$

$\boxed{x=\{-5,1\}}$