Question

resolver equações atraves de determinante?

Answer 1

$\left| \begin{array}{rcr} x & 4 \\ x^2 & 1 \end{array} \right| = 0\\\\\\ x.1-x^2.4=0\\ x-4x^2=0\\ 4x-x=0\\ x(4x-1)=0\\ x=0\\ e\\ 4x-1=0\\ 4x=1\\ x=\frac{1}{4}$

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$\left| \begin{array}{rcr} 3 & 2 & x \\ 1 & -2 & x\\ 2 & -1 & x \end{array} \right|=8\\\\\\ 3.(-2).x+2.x.2+x.(-1).1-x.(-2).2-2.1.x-3.(-1).x=8\\ -6x+4x-x+4x-2x+3x=8\\ 2x=8\\ x=\frac{8}{2}\\ x=4$