3. Solve the simultaneous equations \[ \begin{array}{r}x+7 y=64 \\ x+3 y=28\end{array} \]

Solve the system of equations \( x+7y=64;x+3y=28 \). Solve the system of equations by following steps: - step0: Solve using the substitution method: \(\left\{ \begin{array}{l}x+7y=64\\x+3y=28\end{array}\right.\) - step1: Solve the equation: \(\left\{ \begin{array}{l}x=64-7y\\x+3y=28\end{array}\right.\) - step2: Substitute the value of \(x:\) \(64-7y+3y=28\) - step3: Add the terms: \(64-4y=28\) - step4: Move the constant to the right side: \(-4y=28-64\) - step5: Subtract the numbers: \(-4y=-36\) - step6: Change the signs: \(4y=36\) - step7: Divide both sides: \(\frac{4y}{4}=\frac{36}{4}\) - step8: Divide the numbers: \(y=9\) - step9: Substitute the value of \(y:\) \(x=64-7\times 9\) - step10: Simplify: \(x=1\) - step11: Calculate: \(\left\{ \begin{array}{l}x=1\\y=9\end{array}\right.\) - step12: Check the solution: \(\left\{ \begin{array}{l}x=1\\y=9\end{array}\right.\) - step13: Rewrite: \(\left(x,y\right) = \left(1,9\right)\) The solution to the simultaneous equations \( \begin{array}{r}x+7y=64 \\ x+3y=28\end{array} \) is \( (x,y) = (1,9) \).