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

+4.24, -4.24

Explanation:

We are given:

`5u^2 - 90 = 0`

Simply move 90 to the right hand side and solve:

`5u^2 = 90\\\\\\u^2 = (90)/(5) \\\\\\\u^2 = 18\\`

`u = √(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.