Pré-Vestibular ⇒ (UFLA - 2008) Matrizes: Produto

[Doug]

Faça o produto das matrizes e determine o valor de [tex3]x.[/tex3]

• [tex3]\left(\begin{array}{ccc} x & 1 & x \end{array}\right)\cdot\left(\begin{array}{cc} 2 & 3\\ x & x\\ 2 & 3 \end{array}\right)\cdot \left(\begin{array}{c} 4 \\ 5\end{array}\right)=\left(\begin{array}{c} 5 \end{array}\right)[/tex3]

[Natan]

• [tex3]\left(\begin{array}{ccc} x & 1 & x \end{array}\right)\cdot \left(\begin{array}{cc} 2 & 3\\ x & x\\ 2 & 3 \end{array}\right)= \left(\begin{array}{cc} 2x+x+2x && 3x+x+3x \end{array}\right)=\left(\begin{array}{cc} 5x & 7x \end{array}\right).[/tex3]

• [tex3]\left(\begin{array}{cc} 5x & 7x \end{array}\right)\cdot\left(\begin{array}{c} 4 \\ 5\end{array}\right)=\left(\begin{array}{c} 20x+35x \end{array}\right)=\left(\begin{array}{c} 55x \end{array}\right).[/tex3]

• [tex3]\left(\begin{array}{c} 55x \end{array}\right)=\left(\begin{array}{c} 5 \end{array}\right) \Longrightarrow 55x=5 \Longrightarrow x=\frac{1}{11}.[/tex3]