Question

Which of the following is a solution to the equation x^2=-81?

A. x=9
B. This equation has no real solution.
C. All real numbers.
D. x=-9

Answer 1

It’s B. Because whatever times itself will always be positive whether it’s negative or positive. The outcome will always be positive.

Answer 2

The answer is:

B. This equation has no real solution

Work/explanation:

To solve this equation, we square-root both sides:

`\sf{x^2=-81}`

`\sf{√(x^2) =√(-81)}`

And here things begin to happen. We cannot take the square root of a negative number.

So this leads us to the conclusion that this equation doesn't have a solution in the "Real Numbers" set.

However, we do have a solution in the "Complex Numbers" set.

Hence, B is the answer.