Rational Expressions and Radical Expressions

**illeatyourxface** · Jul 9th 2009, 07:33 PM

I just want to check my answers with someone because im not sure i am correct...

1. 12u cubed/7v to the fifth * 14v squared/3u =
8 u squared/ v cubed

2. 9x * 4/x =
36?

3. x squared -3x +2/x squared -4x +4 divided by x squared -2x +1/ 3x squared -12 =

3(x+2)/ (x-1)

4. 15 divided by 5x/x+1 =
3(x+1) / x

5. 6x/x-2 divided by 3x =
2/x-2

**yeongil** · Jul 9th 2009, 07:43 PM

You really should learn to type in LaTex. I can barely read your post.

1. 12u cubed/7v to the fifth * 14v squared/3u =
8 u squared/ v cubed

You mean this?
$\frac{12u^3}{7v^5} \cdot \frac{14v^2}{3u}$
If so, then
$\frac{12u^3}{7v^5} \cdot \frac{14v^2}{3u} = \frac{4u^2}{v^3} \cdot \frac{2}{1} = \frac{8u^2}{v^3}$
It's correct.

2. 9x * 4/x =
36?

You mean this?
$9x \cdot \frac{4}{x}$
If so, and assuming that x isn't 0, then 36 is right.

3. x squared -3x +2/x squared -4x +4 divided by x squared -2x +1/ 3x squared -12 =

3(x+2)/ (x-1)

I'm not even touching this one.

4. 15 divided by 5x/x+1 =
3(x+1) / x

You mean this?
$15 \div \frac{5x}{x + 1}$
$= 15 \cdot \frac{x + 1}{5x} = \frac{3(x + 1)}{x}$

5. 6x/x-2 divided by 3x =
2/x-2

You mean this?
$\frac{6x}{x - 2} \div 3x$
$= \frac{6x}{x - 2} \cdot \frac{1}{3x} = \frac{2}{x - 2}$

01

**illeatyourxface** · Jul 9th 2009, 07:48 PM

Thanks again,
how would you solve problem involving addition???

ex) x/ (x squared-9) + 3/(x squared-9)

**pickslides** · Jul 9th 2009, 07:49 PM

Originally Posted by illeatyourxface

I just want to check my answers with someone because im not sure i am correct...

1. 12u cubed/7v to the fifth * 14v squared/3u =
8 u squared/ v cubed

$\frac{12u^3}{7v^5}\times\frac{14v^2}{3u}$

$=\frac{12u^3\times 14v^2}{7v^5\times 3u}$

$=\frac{12u^3\times 14v^2}{7v^5\times 3u}$

$=\frac{8u^3\times v^2}{v^5\times u}$

$=8u^2\times v^{-3}$

$=\frac{8u^2}{ v^{-3}}$

**yeongil** · Jul 9th 2009, 07:51 PM

Originally Posted by illeatyourxface

Thanks again,
how would you solve problem involving addition???

ex) x/ (x squared-9) + 3/(x squared-9)

If the denominators are the same, just add the numerators up, like this:
$\frac{x}{x^2 - 9} + \frac{3}{x^2 - 9} = \frac{x + 3}{x^2 - 9}$

But we're not done, because the denominator can be factored:
$\frac{x + 3}{x^2 - 9} = \frac{x + 3}{(x + 3)(x - 3)}$

Cancel out the x + 3, and the answer is
$\frac{1}{x - 3}$

01

**illeatyourxface** · Jul 9th 2009, 07:53 PM

Originally Posted by pickslides

$\frac{12u^3}{7v^5}\times\frac{14v^2}{3u}$

$=\frac{12u^3\times 14v^2}{7v^5\times 3u}$

$=\frac{12u^3\times 14v^2}{7v^5\times 3u}$

$=\frac{8u^3\times v^2}{v^5\times u}$

$=8u^2\times v^{-3}$

$=\frac{8u^2}{ v^{-3}}$

I thought negative exponents were used only if you moved it from the top or bottom...??

**Stroodle** · Jul 9th 2009, 07:55 PM

Originally Posted by illeatyourxface

3. x squared -3x +2/x squared -4x +4 divided by x squared -2x +1/ 3x squared -12 =

Do you mean:

$\frac{x^2-3x+2}{x^2-4x+4}\div\frac{x^2-2x+1}{3x^2-12}$

$=\frac{(x-2)(x-1)}{(x-2)^2}\div\frac{(x-1)^2}{3(x+2)(x-2)}$

$=\frac{3(x-2)^2(x+2)(x-1)}{(x-2)^2(x-1)^2}$

$=\frac{3(x+2)}{x-1}$

**illeatyourxface** · Jul 9th 2009, 07:57 PM

okayyy how would you add or subtract if the demoninator was different?

ex)

4/x cubed y + 7/x y squared

**illeatyourxface** · Jul 9th 2009, 07:58 PM

and im really sorry if this is confusing i dont know how to type in LAtex, im sorrry

**Stroodle** · Jul 9th 2009, 08:06 PM

$\frac{12u^3}{7v^5}\times\frac{14v^2}{3u}$

$=\frac{168u^3v^2}{21v^5u}$

$=\frac{8u^2}{v^3}$

edit* Oops I didn't notice that Yeongil already answered this one correctly...

**pickslides** · Jul 9th 2009, 08:13 PM

Originally Posted by illeatyourxface

I thought negative exponents were used only if you moved it from the top or bottom...??

yep my bad, forgot to remove the "-" sign

**illeatyourxface** · Jul 9th 2009, 08:34 PM

to solve it.... would it be like

4/ x cubed y + 7/ x y squared =

(4)(y) + (7) (x squared) / (x cubed y)(x y squared) ????

**Stroodle** · Jul 9th 2009, 08:44 PM

Do you mean:

$\frac{4}{x^3y}+\frac{7}{xy^2}$

$=\frac{4y}{x^3y^2}+\frac{7x^2}{x^3y^2}$

$=\frac{4y+7x^2}{x^3y^2}$

**illeatyourxface** · Jul 9th 2009, 09:11 PM

okay soo if you are subtracting...

11/3x - 5/6x =

33x -5 / 6x ?

**Stroodle** · Jul 9th 2009, 09:16 PM

$\frac{11}{3x}-\frac{5}{6x}$

To make the denominator the same for both terms you multiply the top and bottom of the first term by 2

$=\frac{22}{6x}-\frac{5}{6x}$

$=\frac{22-5}{6x}$

$=\frac{17}{6x}$

Thread: Rational Expressions and Radical Expressions

LinkBack

Thread Tools

Display

Rational Expressions and Radical Expressions

Similar Math Help Forum Discussions

Radical Expressions

Simplifying Radical Expressions

Simplifying radical expressions

Simplifyimg Radical Expressions

radical expressions

Search Tags