Question

Simplify the radical expression.
the square root of 72x^2

Answer 1

What do you think?

Answer 2

\[36\sqrt{x ^{2}}\]?

Answer 3

You divided by 2. Why would that be right? You need to find perfect squares and remove them.

72 = 2*36 = \(2^{2}\cdot 18 = 2^{2}\cdot 3^{2}\cdot 2\)

So, 72 has perfect squares of both 2 and 3.

Answer 4

Okay, I think I understand now! thanks!

Answer 5

The \(x^{2}\)-part is a little tricky.

Answer 6

Yes, indeed — you can't blindly replace \(\sqrt{x^2}\) with \(x\) unless you somehow know that \(x>0\)