# Math Help - Surds (i think)

1. ## Surds (i think)

Hi im new! wonder if anyone can help me with this...

Express 36 / 5 - (square root)7

in the form a + b (square root)7, where a and b are integers

2. Originally Posted by RubbishAtMaths
Hi im new! wonder if anyone can help me with this...

Express 36 / 5 - (square root)7

in the form a + b (square root)7, where a and b are integers

I assume that you mean:

$\dfrac{36}{5-\sqrt{7}} = \dfrac{36}{5-\sqrt{7}} \cdot \dfrac{5+\sqrt{7}}{5+\sqrt{7}} = \dfrac{180+36\sqrt{7}}{25-7}=10+2\sqrt{7}$

3. cheers matey!