To find the value of \( k \) in the equation \( 7 + 2k^2 = 25 \), we can do the following steps:
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We start with the equation: \[ 7 + 2k^2 = 25 \]
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Next, we want to get rid of the 7 on the left side, so we subtract 7 from both sides: \[ 2k^2 = 25 - 7 \] This gives us: \[ 2k^2 = 18 \]
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Now, we need to make \( k^2 \) by itself, so we divide both sides by 2: \[ k^2 = \frac{18}{2} \] Which simplifies to: \[ k^2 = 9 \]
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Finally, we take the square root of both sides to find \( k \): \[ k = \pm 3 \] This means that \( k \) can be either 3 or -3.
So, the answer is: \[ k = 3 \quad \text{or} \quad k = -3 \]
In simpler words, the values of \( k \) are 3 and -3! The solution set is \( { 3, -3 } \).