Question

The roots of the equation $\left| \begin{matrix} x & 0 & 8 \\ 4 & 1 & 3 \\ 2 & 0 & x \end{matrix} \right| = 0$are equal to.

• A. $( - 4,4)$
• B. $(2, - 4)$
• C. $(2,4)$
• D. $(2,8)$

Answer 1

Answer: (A)

$( - 4,4)$

Answer 2

We have $\left| \begin{matrix} x & 0 & 8 \\ 4 & 1 & 3 \\ 2 & 0 & x \end{matrix} \right| = 0$

$\therefore$ $\Delta = x(x - 0) - 0(4x - 6) + 8(0 - 2)$

or $x^{2} - 16 = 0$ $\Rightarrow$ $x = 4, - 4$.