Resposta :
[tex]a) \begin{bmatrix}y=10+x+9-2x\\ x=3\end{bmatrix}\\\\y=10+3+9-2\cdot \:3\\\\y=16\\\\y=16,\:x=3[/tex]
[tex]b) \begin{bmatrix}y=-x+6\\ x=8\end{bmatrix}\\\\\begin{bmatrix}x=8\end{bmatrix}\\\\y=-8+6\\\\y=-2\\\\y=-2,\:x=8[/tex]
[tex]c) \begin{bmatrix}y=x\cdot \:2-4x-3x+8\\ x=-1\end{bmatrix}\\\\\begin{bmatrix}x=-1\end{bmatrix}\\\\y=\left(-1\right)\cdot \:2-4\left(-1\right)-3\left(-1\right)+8\\\\y=13\\\\y=13,\:x=-1[/tex]
[tex]d) \begin{bmatrix}y=x\cdot \:3-2x+1\\ x=-2\end{bmatrix}\\\\\begin{bmatrix}x=-2\end{bmatrix}\\\\y=\left(-2\right)\cdot \:3-2\left(-2\right)+1\\\\y=-1\\\\y=-1,\:x=-2[/tex]
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