How do you solve x^2=90?

Jul 4, 2017

x=+-3sqrt10

Explanation:

Taking the square root of any number gives you two answers, one positive and one negative e.g. -2 x -2 =4
Square root of 90 = square root of 9 x 10
You can root the 3 to give 3sqrt10

Jul 4, 2017

$x = 3 \sqrt{10} \leftarrow \text{ exact value}$

Explanation:

Using the 'Principle square root'. That is, the positive one.

Square root both sides

$\sqrt{{x}^{2}} = \sqrt{90}$

$x = \sqrt{{3}^{2} \times 10}$

$x = 3 \sqrt{10} \leftarrow \text{ exact value}$

Not that the decimal equivalent would be rounded and thus not as precise.