To find \( k \) in the equation \( 7 + 2k^2 = 25 \):
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Start with the equation: \[ 7 + 2k^2 = 25 \]
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Subtract 7 from both sides: \[ 2k^2 = 18 \]
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Divide by 2: \[ k^2 = 9 \]
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Take the square root: \[ k = \pm 3 \]
Thus, the values of \( k \) are \( 3 \) and \( -3 \). The solution set is \( { 3, -3 } \).