# Simplifying Expressions... Not sure which kinds

• May 21st 2008, 05:02 PM
jscalalamoboy
Simplifying Expressions... Not sure which kinds
Ok, I'm going to post 3 so I can be sure of how to do each kind.
$
\frac {6}{x^2-9x+20} * (5x-25)
$

$
\frac {2x-6}{x^2+5x-24} * \frac {x^2+6x-16}{3x}
$

$
\frac {(\frac {3x^2}{8x^5} * 2x^3)}{\frac {9x}{8x^2}}
$
• May 21st 2008, 05:25 PM
r_maths
Quote:

Originally Posted by jscalalamoboy
Ok, I'm going to post 3 so I can be sure of how to do each kind.
$
\frac {6}{x^2-9x+20} * (5x-25)
$

$\frac{6\cdot 5(x-5)}{(x-4)(x-5)}=\frac{30(x-5)}{(x-4)(x-5)}=\frac{30}{(x-4)}
$

---

$\frac{(3x^{2})(2x^{3})}{8x^{5}}\times \frac{8x^{2}}{9x}$

$\frac{3x(2x^{4})}{9x(8x^{3})}=\frac{2x^{4}}{3(8x^{ 3})}=\frac{2x^{4}}{24x^{3}}=\frac{x}{12}
$
• May 21st 2008, 05:35 PM
icemanfan
Quote:

Originally Posted by jscalalamoboy
Ok, I'm going to post 3 so I can be sure of how to do each kind.

$
\frac {2x-6}{x^2+5x-24} * \frac {x^2+6x-16}{3x}
$

$\frac{2x-6}{x^2+5x-24} = \frac{2(x-3)}{(x+8)(x-3)} = \frac{2}{x+8}$

$\frac{x^2+6x-16}{3x} = \frac{(x+8)(x -2)}{3x}$

so the product is $\frac{2}{x+8}\cdot \frac{(x+8)(x-2)}{3x}$

$= \frac{2(x+8)(x-2)}{3x(x+8)} = \frac{2(x-2)}{3x}$