Question

Look at the expressions below.

2√8 x √20
Which of these is equivalent to this expression?
A. 2√28
B. 5
C. 8√10
D. 32√10

Answer 1

First, we can write 2√8 as 2 x √8. This will make the next calculations easier.

So the problem becomes 2 x √8 x √20.

We can group together √8 and √20, to get √160.

And we have: 2√160.

However, this can be simplified further, as 16x10 = 160, and so we obtain the final answer of 8√10.

C is correct.

Answer 2

8 sqrt(10)

Explanation:

2 sqrt(8) * sqrt(20)

We know sqrt(a) * sqrt(b) = sqrt(ab)

2 sqrt(8) * sqrt(20)

2 sqrt(160)

2 sqrt(16*10)

2 sqrt(16) sqrt(10)

2 *4 sqrt(10)

8 sqrt(10)