$\left\{\begin{array} { l } 2x-4y=10 \\ x=40-5y\end{array} \right.$
Substitute the given value of $x$ into the equation $2x-4y=10$$2\left( 40-5y \right)-4y=10$
Solve the equation for $y$$y=5$
Substitute the given value of $y$ into the equation $x=40-5y$$x=40-5 \times 5$
Solve the equation for $x$$x=15$
The possible solution of the system is the ordered pair $\left( x, y\right)$$\left( x, y\right)=\left( 15, 5\right)$
Check if the given ordered pair is the solution of the system of equations$\left\{\begin{array} { l } 2 \times 15-4 \times 5=10 \\ 15+5 \times 5=40\end{array} \right.$
Simplify the equalities$\left\{\begin{array} { l } 10=10 \\ 40=40\end{array} \right.$
Since all of the equalities are true, the ordered pair is the solution of the system$\left( x, y\right)=\left( 15, 5\right)$