Solving Simple Quadratic Equations Quick Check

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Question
Use inspection to solve the equation x2=81, then select the complete solution set below. If there are no real solutions, select “There are no real solutions.”(1 point)
Responses

{9}
left brace 9 right brace

{−9}
left brace negative 9 right brace

{−9,9}
left brace negative 9 comma 9 right brace

There are no real solutions.
There are no real solutions.
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1 answer

To solve the equation \(x^2 = 81\) by inspection, we can take the square root of both sides. The equation implies that:

\[ x = \pm \sqrt{81} \]

Calculating the square root, we find:

\[ \sqrt{81} = 9 \]

Thus, the solutions are:

\[ x = 9 \quad \text{and} \quad x = -9 \]

Therefore, the complete solution set is:

\[ {-9, 9} \]

The correct response is:

\({-9, 9}\)