Question

how fo u solve 7xsqaured=-21

Answer 1

Explanation:

$7x^2=-21$

First we have to divide both sides by 7:

$\begin{gathered} \frac{7x^2}{7}=\frac{-21}{7} \\ x^2=-3 \end{gathered}$

And now we have to take square root on both sides:

$\begin{gathered} \sqrt[]{x^2}=\pm\sqrt[]{-3} \\ x=\pm\sqrt[]{-3} \end{gathered}$

Since the number inside the square root is negative we can rewrite it as:

$x=\pm\sqrt[]{i^23}=\pm i\sqrt[]{3}$

This is a quadratic equation, so it has two solutions.

Answer:

The solutions are:

• i√3

,

• -i√3