# Math Help - Multiplying numbers with square roots

1. ## 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.
${\left({4}{x}-{5}\sqrt{{{6}}}\right)}{\left({4}{x}+{5}\sqrt{{{6}}}\right)}$

2. ## Re: Multiplying numbers with square roots

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.
${\left({4}{x}-{5}\sqrt{{{6}}}\right)}{\left({4}{x}+{5}\sqrt{{{6}}}\right)}$
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 $a=4x \quad b = 5\sqrt{6}$