Question

1) Resolva a equação
a) -18
b) 18
C) -20
d) 20​

Answer 1

$\begin{vmatrix}1 & 0 & 2\\2 & 4 & 1\\3 & 2 & 0\end{vmatrix}=|x|\\\\\\\begin{vmatrix}1 & 0 & 2\\2 & 4 & 1\\3 & 2 & 0\end{vmatrix} \ \begin{matrix}1 & 0 \\2 & 4\\3 & 2\end{matrix}=|x|\\\\\\(1\cdot 4 \cdot 0) +(0\cdot 1 \cdot 3)+(2\cdot 2 \cdot 2)-(3\cdot 4 \cdot 2)-(2\cdot 1 \cdot 1)-(0\cdot 2 \cdot 0)=x\\\\0 +0+8-24-2-0=x\\\\-18=x\\\\x=-18$

Resposta: a