Question

EXERCISE 5 (a) Solve for \( x \) and \( y \) by using the method of substitution: (1) \( x-y=8 \) and \( 2 x+y=10 \) (2) \( 3 x-y=2 \) and \( 7 x-2 y=8 \) (3) \( 3 x+5 y=8 \) and \( x-2 y=-1 \) (4) \( 7 x-3 y=41 \) and \( 3 x-y=17 \)

Ask by Lewis Mcguire. in South Africa
Mar 11,2025

Upstudy AI Solution

Tutor-Verified Answer

Answer

The solutions are: 1. \( (6, -2) \) 2. \( (4, 10) \) 3. \( (1, 1) \) 4. \( (5, -2) \)

Solution

Solve the system of equations by following steps: - step0: Solve using the substitution method: \(\left\{ \begin{array}{l}x-y=8\\2x+y=10\end{array}\right.\) - step1: Solve the equation: \(\left\{ \begin{array}{l}x=8+y\\2x+y=10\end{array}\right.\) - step2: Substitute the value of \(x:\) \(2\left(8+y\right)+y=10\) - step3: Simplify: \(16+3y=10\) - step4: Move the constant to the right side: \(3y=10-16\) - step5: Subtract the numbers: \(3y=-6\) - step6: Divide both sides: \(\frac{3y}{3}=\frac{-6}{3}\) - step7: Divide the numbers: \(y=-2\) - step8: Substitute the value of \(y:\) \(x=8-2\) - step9: Calculate: \(x=6\) - step10: Calculate: \(\left\{ \begin{array}{l}x=6\\y=-2\end{array}\right.\) - step11: Check the solution: \(\left\{ \begin{array}{l}x=6\\y=-2\end{array}\right.\) - step12: Rewrite: \(\left(x,y\right) = \left(6,-2\right)\) Solve the system of equations \( 3 x-y=2;7 x-2 y=8 \). Solve the system of equations by following steps: - step0: Solve using the substitution method: \(\left\{ \begin{array}{l}3x-y=2\\7x-2y=8\end{array}\right.\) - step1: Solve the equation: \(\left\{ \begin{array}{l}y=-2+3x\\7x-2y=8\end{array}\right.\) - step2: Substitute the value of \(y:\) \(7x-2\left(-2+3x\right)=8\) - step3: Simplify: \(x+4=8\) - step4: Move the constant to the right side: \(x=8-4\) - step5: Subtract the numbers: \(x=4\) - step6: Substitute the value of \(x:\) \(y=-2+3\times 4\) - step7: Calculate: \(y=10\) - step8: Calculate: \(\left\{ \begin{array}{l}x=4\\y=10\end{array}\right.\) - step9: Check the solution: \(\left\{ \begin{array}{l}x=4\\y=10\end{array}\right.\) - step10: Rewrite: \(\left(x,y\right) = \left(4,10\right)\) Solve the system of equations \( 7 x-3 y=41;3 x-y=17 \). Solve the system of equations by following steps: - step0: Solve using the substitution method: \(\left\{ \begin{array}{l}7x-3y=41\\3x-y=17\end{array}\right.\) - step1: Solve the equation: \(\left\{ \begin{array}{l}7x-3y=41\\y=-17+3x\end{array}\right.\) - step2: Substitute the value of \(y:\) \(7x-3\left(-17+3x\right)=41\) - step3: Simplify: \(-2x+51=41\) - step4: Move the constant to the right side: \(-2x=41-51\) - step5: Subtract the numbers: \(-2x=-10\) - step6: Change the signs: \(2x=10\) - step7: Divide both sides: \(\frac{2x}{2}=\frac{10}{2}\) - step8: Divide the numbers: \(x=5\) - step9: Substitute the value of \(x:\) \(y=-17+3\times 5\) - step10: Calculate: \(y=-2\) - step11: Calculate: \(\left\{ \begin{array}{l}x=5\\y=-2\end{array}\right.\) - step12: Check the solution: \(\left\{ \begin{array}{l}x=5\\y=-2\end{array}\right.\) - step13: Rewrite: \(\left(x,y\right) = \left(5,-2\right)\) Solve the system of equations \( 3 x+5 y=8;x-2 y=-1 \). Solve the system of equations by following steps: - step0: Solve using the substitution method: \(\left\{ \begin{array}{l}3x+5y=8\\x-2y=-1\end{array}\right.\) - step1: Solve the equation: \(\left\{ \begin{array}{l}3x+5y=8\\x=-1+2y\end{array}\right.\) - step2: Substitute the value of \(x:\) \(3\left(-1+2y\right)+5y=8\) - step3: Simplify: \(-3+11y=8\) - step4: Move the constant to the right side: \(11y=8+3\) - step5: Add the numbers: \(11y=11\) - step6: Divide both sides: \(\frac{11y}{11}=\frac{11}{11}\) - step7: Divide the numbers: \(y=1\) - step8: Substitute the value of \(y:\) \(x=-1+2\times 1\) - step9: Substitute back: \(x=-1+2\) - step10: Calculate: \(x=1\) - step11: Calculate: \(\left\{ \begin{array}{l}x=1\\y=1\end{array}\right.\) - step12: Check the solution: \(\left\{ \begin{array}{l}x=1\\y=1\end{array}\right.\) - step13: Rewrite: \(\left(x,y\right) = \left(1,1\right)\) Here are the solutions for each system of equations using the method of substitution: 1. For the equations \( x - y = 8 \) and \( 2x + y = 10 \): - The solution is \( (x, y) = (6, -2) \). 2. For the equations \( 3x - y = 2 \) and \( 7x - 2y = 8 \): - The solution is \( (x, y) = (4, 10) \). 3. For the equations \( 3x + 5y = 8 \) and \( x - 2y = -1 \): - The solution is \( (x, y) = (1, 1) \). 4. For the equations \( 7x - 3y = 41 \) and \( 3x - y = 17 \): - The solution is \( (x, y) = (5, -2) \). If you need further explanations or steps for any specific system, feel free to ask!

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Let’s dive into solving those equations using substitution! (1) From \( x - y = 8 \), we get \( x = y + 8 \). Substituting this into the second equation \( 2x + y = 10 \): \( 2(y + 8) + y = 10 \) simplifies to \( 3y + 16 = 10 \), resulting in \( 3y = -6 \) or \( y = -2 \). Now substituting \( y \) back into \( x = y + 8 \) gives \( x = 6 \). So, \( x = 6 \) and \( y = -2 \). (2) From \( 3x - y = 2 \), we have \( y = 3x - 2 \). Substituting into \( 7x - 2y = 8 \) gives: \( 7x - 2(3x - 2) = 8 \) simplifies to \( 7x - 6x + 4 = 8 \), leading to \( x = 4 \). Plugging \( x \) back into \( y = 3x - 2 \) gives \( y = 10 \). Thus, \( x = 4 \) and \( y = 10 \). (3) From \( x - 2y = -1 \), we rewrite it as \( x = 2y - 1 \) and substitute into \( 3x + 5y = 8 \): \( 3(2y - 1) + 5y = 8 \) simplifies to \( 6y - 3 + 5y = 8 \) or \( 11y - 3 = 8 \), which leads to \( 11y = 11 \) giving \( y = 1 \). Substituting \( y \) back gives \( x = 1 \). So, \( x = 1 \) and \( y = 1 \). (4) From \( 3x - y = 17 \) we get \( y = 3x - 17 \). Substituting this into \( 7x - 3y = 41 \): \( 7x - 3(3x - 17) = 41 \) simplifies to \( 7x - 9x + 51 = 41 \), leading to \( -2x + 51 = 41 \) or \( -2x = -10 \), so \( x = 5 \). Plugging back gives \( y = 3(5) - 17 \), resulting in \( y = -2 \). Hence, \( x = 5 \) and \( y = -2 \). Now you have the solutions for all four systems! Happy solving!

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