Simplify √50 × √8

Step by step

The question

Question: work out √50 × √8.

1 Multiply

Rule: two roots times each other make one root of the two numbers times each other.

So it is the root of 50 times 8.

Careful!

This works for times, not for plus.

√9 + √16 is 3 + 4 = 7, but √25 is 5.

50 times 8 is 400.

2 Simplify the root

400 is a square number: 20 times 20 is 400.

So √400 is 20.

So we get 20.

So √50 × √8 = 20.

3 Check

Let's check with a calculator.

The start is about 20.00.

The answer is about 20.00 too.

So it is right!

Let's look back.

First: multiply.

Then: simplify the root.

Last: check.