## Precalculus (6th Edition) Blitzer

a) Yes, the point $\left( 4,-1 \right)$ satisfies the equation $x+2y=2$. b) Yes, the point $\left( 4,-1 \right)$ satisfies the equation $x-2y=6$.
(a). Consider the point $\left( 4,-1 \right)$ as $\left( x,y \right)$. Now put $x=4$ and $y=-1$ to satisfy the equation $x+2y=2$. \begin{align} & x+2y=2 \\ & 4+2\left( -1 \right)=2 \\ & 4-2=2 \\ & 2=2 \end{align} Hence, the $\left( 4,-1 \right)$ satisfies $x+2y=2$. (b). Consider the point $\left( 4,-1 \right)$ as $\left( x,y \right)$. Now put $x=4$ and $y=-1$ to satisfy the equation $x-2y=6$. \begin{align} & x-2y=6 \\ & 4-2\left( -1 \right)=6 \\ & 4+2=6 \\ & 6=6 \end{align} Hence, the $\left( 4,-1 \right)$ satisfies $x-2y=6$.