To determine which equation matches the solution set of {5}, we need to solve each of the equations and see which one results in \( x = 5 \).
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Equation: \( \frac{3x}{5} + 4 = 7 \)
\[ \frac{3x}{5} + 4 = 7 \] Subtract 4 from both sides: \[ \frac{3x}{5} = 3 \] Multiply both sides by 5: \[ 3x = 15 \] Divide by 3: \[ x = 5 \]
- This equation has the solution \( x = 5 \), so this is correct.
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Equation: \( x + x - 9 = 1 + x \)
Combine like terms: \[ 2x - 9 = 1 + x \] Subtract \( x \) from both sides: \[ x - 9 = 1 \] Add 9 to both sides: \[ x = 10 \]
- This equation does not have \( x = 5 \) as a solution, so this is incorrect.
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Equation: \( x^2 - 10 = 15 \)
Add 10 to both sides: \[ x^2 = 25 \] Take the square root: \[ x = 5 \quad \text{or} \quad x = -5 \]
- This equation has the solutions \( x = 5 \) and \( x = -5 \), so it doesn't match the specific solution set {5} since it includes -5 as well.
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Equation: \( 2x - 20 = 30 \)
Add 20 to both sides: \[ 2x = 50 \] Divide by 2: \[ x = 25 \]
- This equation does not have \( x = 5 \) as a solution, so this is incorrect.
Summary:
The equation that matches the solution set of {5} is \( \frac{3x}{5} + 4 = 7 \), making it the only correct choice. The other equations either yield different values or include additional solutions beyond just \( x = 5 \).