# Multiplying numbers with square roots

• September 29th 2012, 03:01 PM
DasRabbit
Multiplying numbers with square roots
I attempted this problem but got it incorrect. If someone could guide me step by step on how to do this problem it would be greatly appreciated.
http://www.imathas.com/cgi-bin/mimet...%5Cright%29%7D
• September 29th 2012, 03:07 PM
TheEmptySet
Re: Multiplying numbers with square roots
Quote:

Originally Posted by DasRabbit
I attempted this problem but got it incorrect. If someone could guide me step by step on how to do this problem it would be greatly appreciated.
http://www.imathas.com/cgi-bin/mimet...{{6}}}\right)}

This is the product of special binomials. You can just use the distributive law or the fact that

$(a-b)(a+b)=a^2-b^2$

In your case $a=4x \quad b = 5\sqrt{6}$