Question

Solve 5u^2 — 90 = 0, where u is a real number.

Round your answer to the nearest hundredth.

If there is more than one solution, separate them with commas.

If there is no solution, click on "No solution".

Answer 1

Answer:

+4.24, -4.24

Step-by-step explanation:

We are given:

$5u^2 - 90 = 0$

Simply move 90 to the right hand side and solve:

$5u^2 = 90\\\\\\u^2 = \frac{90}{5} \\\\\\\u^2 = 18$

$u = \sqrt{18}$

It is noteworthy that a square root has two solutions, the positive and the negative of a number i.e. ±x

This is because $(+x)^2 = x^2$ and $(-x)^2 = -x * -x = x^2$

Hence:

$u =$ ±$4.2426$ ≅ ±4.24

The solutions of the equation are +4.24 and -4.24.