Systems of Equations Solve the system of equations by graphing. System of Equations \[ \begin{array}{l} 3 y-9 x=-18 \\ -y-4 x=-15 \end{array} \] Identify the Solution to the System of Equations as an Ordered Pair. Write \( D N E \) if the Solution does not exist. Write oo ( \( \infty \) ) if infinitely many solutions exist: Solution: \( \square \)

Solve the system of equations \( 3y-9x=-18;-y-4x=-15\). Solve the system of equations by following steps: - step0: Solve using the substitution method: \(\left\{ \begin{array}{l}3y-9x=-18\\-y-4x=-15\end{array}\right.\) - step1: Solve the equation: \(\left\{ \begin{array}{l}3y-9x=-18\\y=15-4x\end{array}\right.\) - step2: Substitute the value of \(y:\) \(3\left(15-4x\right)-9x=-18\) - step3: Simplify: \(45-21x=-18\) - step4: Move the constant to the right side: \(-21x=-18-45\) - step5: Subtract the numbers: \(-21x=-63\) - step6: Change the signs: \(21x=63\) - step7: Divide both sides: \(\frac{21x}{21}=\frac{63}{21}\) - step8: Divide the numbers: \(x=3\) - step9: Substitute the value of \(x:\) \(y=15-4\times 3\) - step10: Calculate: \(y=3\) - step11: Calculate: \(\left\{ \begin{array}{l}x=3\\y=3\end{array}\right.\) - step12: Check the solution: \(\left\{ \begin{array}{l}x=3\\y=3\end{array}\right.\) - step13: Rewrite: \(\left(x,y\right) = \left(3,3\right)\) The solution to the system of equations is \( (x, y) = (3, 3) \). Therefore, the solution to the system of equations is an ordered pair, and the answer is \( \square \).