Let's go over the equation step by step to see if there are any errors in Angie's solution.
The original equation is: \[ -x + 7 = -11 \]
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Subtract 7 from both sides: \[ -x + 7 - 7 = -11 - 7 \] This simplifies to: \[ -x = -18 \]
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Now, multiply both sides by -1 to solve for x: \[ x = 18 \]
Now let's analyze the possible errors in Angie's solution based on the options provided:
A. She subtracted -11 and -7 incorrectly: This option is incorrect, as Angie didn’t actually do this step correctly. She correctly subtracted 7 from both sides.
B. She didn't make any errors: This is incorrect, as the final answer is not stated correctly. The solution is \( x = 18\) and not \( -18 \).
C. She didn't divide both sides by -1: This is correct because after finding \(-x = -18\), she needed to multiply both sides by \(-1\) to get the correct positive solution: \(x = 18\).
So, the correct answer is C. She didn't divide both sides by -1.