## Precalculus (10th Edition)

$\left\{\left(\dfrac{4}{3},\dfrac{1}{5}\right)\right\}$
We are given the system of equations: $\begin{cases} 3x-5y=3\\ 15x+5y=21 \end{cases}$ Use the elimination method. Add the two equations to eliminate $y$ and determine $x$: $3x-5y+15x+5y=3+21$ $18x=24$ $x=\dfrac{24}{18}$ $x=\dfrac{4}{3}$ Determine $y$ using the first equation: $3x-5y=3$ $3\left(\dfrac{4}{3}\right)-5y=3$ $4-5y=3$ $5y=1$ $y=\dfrac{1}{5}$ The solution set of the system is: $\left\{\left(\dfrac{4}{3},\dfrac{1}{5}\right)\right\}$