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Question Find the solution of the system of equations. \[ -3 x-7 y=18 \] \[ 9 x+2 y=3 \] \( \begin{array}{l}\text { Answer Attempt tout of a } \\ (\square), \square) \text { Submit Answer }\end{array} \)

Ask by Savage Martinez. in the United States
Mar 10,2025

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Tutor-Verified Answer

Answer

The solution to the system of equations is \( (1, -3) \).

Solution

1. Write down the system of equations: \[ -3x - 7y = 18 \] \[ 9x + 2y = 3 \] 2. Multiply the first equation by \(3\) to match the coefficient of \(x\) (in absolute value): \[ 3(-3x - 7y) = 3(18) \quad \Rightarrow \quad -9x - 21y = 54 \] 3. Now, add the modified first equation and the second equation to eliminate \(x\): \[ \begin{aligned} (-9x - 21y) + (9x + 2y) &= 54 + 3 \\ (-9x + 9x) + (-21y + 2y) &= 57 \\ -19y &= 57 \end{aligned} \] 4. Solve for \(y\): \[ y = \frac{57}{-19} = -3 \] 5. Substitute \(y = -3\) back into one of the original equations to solve for \(x\). Using the first equation: \[ -3x - 7(-3) = 18 \quad \Rightarrow \quad -3x + 21 = 18 \] \[ -3x = 18 - 21 \quad \Rightarrow \quad -3x = -3 \] \[ x = \frac{-3}{-3} = 1 \] 6. The solution to the system is: \[ (x, y) = (1, -3) \]

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Beyond the Answer

To solve the system of equations given, we can use the substitution or elimination method. Let's start by rearranging the first equation: 1. From \( -3x - 7y = 18 \), we can express \( y \): \( 7y = -3x - 18 \) \( y = -\frac{3}{7}x - \frac{18}{7} \) 2. Now, substitute this expression for \( y \) into the second equation \( 9x + 2y = 3 \): \( 9x + 2\left(-\frac{3}{7}x - \frac{18}{7}\right) = 3 \) Simplifying, we have: \( 9x - \frac{6}{7}x - \frac{36}{7} = 3 \) Clearing the fraction by multiplying through by 7 gives: \( 63x - 6x - 36 = 21 \) Combine like terms: \( 57x = 57 \) Thus, \( x = 1 \). 3. Substitute \( x = 1 \) back into the equation for \( y \): \( y = -\frac{3}{7}(1) - \frac{18}{7} \) \( y = -\frac{3}{7} - \frac{18}{7} = -\frac{21}{7} = -3 \). So, the solution to the system of equations is: \( (1, -3) \). \( \text{Submit Answer: } (1, -3) \)

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