# Help with rationalizing expressions

• Dec 2nd 2008, 01:46 PM
shiel8
Help with rationalizing expressions
I need help with a couple of rationalization questions. I am totally confused.

square root 5x minus 6 / squareroot 5x plus 3

(squareroot 2+y plus squareroot 2-y)/y
• Dec 2nd 2008, 02:23 PM
masters
Quote:

Originally Posted by shiel8
I need help with a couple of rationalization questions. I am totally confused.

square root 5x minus 6 / squareroot 5x plus 3

(squareroot 2+y plus squareroot 2-y)/y

Is it

(1) $\frac{\sqrt{5x-6}}{\sqrt{5x+3}}$ ?

or

(2) $\frac{\sqrt{5x}-6}{\sqrt{5x}+3}$

Also group what's under the radical in your second problem as well.
• Dec 2nd 2008, 02:52 PM
shiel8
http://www.mathhelpforum.com/math-he...6a534c0d-1.gif

for the second questions it's 2+y under squareroot symbol minus 2-y under squareroot symbol all over y

how do you enter info in the format you're using? It'd be much easier to post if I knew how to do that.
• Dec 3rd 2008, 12:16 AM
earboth
Quote:

Originally Posted by shiel8
http://www.mathhelpforum.com/math-he...6a534c0d-1.gif

for the second questions it's 2+y under squareroot symbol minus 2-y under squareroot symbol all over y

how do you enter info in the format you're using? It'd be much easier to post if I knew how to do that.

Have a look here: http://www.mathhelpforum.com/math-he...-tutorial.html

Use a factor such that you get a sum of squares in the denominator:

$\dfrac{\sqrt{5x} - 6}{\sqrt{5x} + 3}=\dfrac{\sqrt{5x} - 6}{\sqrt{5x} + 3} \cdot \dfrac{\sqrt{5x} - 3}{\sqrt{5x} - 3}= \dfrac{5x-9\sqrt{5x} +18}{5x-9}$
• Dec 3rd 2008, 11:21 AM
shiel8
Thanks Earboth.

Hopefully this works right. The other question I need help with is:

$\frac{\sqrt{2+y} + \sqrt{2-y}}{y}$