# Math Homework Help!

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• Aug 21st 2008, 10:11 AM
Peyton Sawyer
Math Homework Help!
1.)
x^2-3x-18/15x+45 divided by 12x/x^2-36

2.)
add and simplyfiy
2/3n^2 + 5/2n
• Aug 21st 2008, 10:16 AM
Chris L T521
Quote:

Originally Posted by Peyton Sawyer
1.)
x^2-3x-18/15x+45 divided by 12x/x^2-36

2.)
add and simplyfiy
2/3n^2 + 5/2n

Is this what you mean? Try to be a little clearer on notation...

$\displaystyle 1.~\frac{\displaystyle\frac{x^2-3x-18}{15x+45}}{\displaystyle\frac{12x}{x^2-36}}$

$\displaystyle 2.~\frac{2}{3n^2}+\frac{5}{2n}$

--Chris
• Aug 21st 2008, 10:20 AM
Peyton Sawyer
u set up #2 perfectly

but #1 is more like this.

x^2-3x-18 divided by
----------
15x+45

x^2-36
-------
12x
• Aug 21st 2008, 10:25 AM
Chris L T521
Quote:

Originally Posted by Peyton Sawyer
u set up #2 perfectly

but #1 is more like this.

x^2-3x-18 divided by x^2-36
---------- --------
15x+45 12x

$\displaystyle \frac{\displaystyle\frac{x^2-3x-18}{15x+45}}{\displaystyle\frac{x^2-36}{12x}}=\frac{x^2-3x-18}{15x+45}\cdot\frac{12x}{x^2-36}=\frac{(x-6)(x+3)}{15(x+3)}\cdot\frac{12x}{(x+6)(x-6)}=\dots$

--Chris
• Aug 21st 2008, 10:29 AM
Peyton Sawyer
thats where i left of too

here are the multiple choice

a. (5x + 30)/4x

b. 4x/(5x - 30)

c. 4x/(5x + 30)

d. 4x/(x + 6)

e. (x + 6)/4x
• Aug 21st 2008, 10:32 AM
Chris L T521
Quote:

Originally Posted by Chris L T521
$\displaystyle \frac{\displaystyle\frac{x^2-3x-18}{15x+45}}{\displaystyle\frac{x^2-36}{12x}}=\frac{x^2-3x-18}{15x+45}\cdot\frac{12x}{x^2-36}=\frac{(x-6)(x+3)}{15(x+3)}\cdot\frac{12x}{(x+6)(x-6)}=\dots$

--Chris

Quote:

Originally Posted by Peyton Sawyer
thats where i left of too

here are the multiple choice

a. (5x + 30)/4x

b. 4x/(5x - 30)

c. 4x/(5x + 30)

d. 4x/(x + 6)

e. (x + 6)/4x

Did you try to simplify this?

$\displaystyle \frac{(x-6)(x+3)}{15(x+3)}\cdot\frac{12x}{(x+6)(x-6)}=\frac{3(4x)(x+3)(x-6)}{3(5)(x+3)(x+6)(x-6)}=\dots$

Just cancel out the terms that bot the numerator and denominator have in common. The answer will become pretty obvious...

--Chris
• Aug 21st 2008, 10:38 AM
Peyton Sawyer
thanks chris!