• October 25th 2006, 08:56 PM
wpcp15
Sorry its late but i just got off work

I need help with some of my problems, Im not sure I did these right
(^ means its an exponent)

(a^3b^3) (ab)^-2

-5x^3 y^3 z^4 over 20x^3 y^7 z^4
• October 25th 2006, 09:11 PM
CaptainBlack
Quote:

Originally Posted by wpcp15
Sorry its late but i just got off work

I need help with some of my problems, Im not sure I did these right
(^ means its an exponent)

(a^3b^3) (ab)^-2

Expand the second bracket:

$(a^3b^3) (ab)^{-2}=a^3 b^3 a^{-2}b^{-2}$

Collect powers of the variables:

$a^3 b^3 a^{-2}b^{-2}=a^{3-2}b^{3-2} =a^1 b^1=a\ b$

Quote:

-5x^3 y^3 z^4 over 20x^3 y^7 z^4
Bring all powers to the same level:

$
{{-5 x^3 y^3 z^4} \over {20 x^3 y^7 z^4}} = \frac{-5}{20} x^3 y^3 z^4 x^{-3} y^{-7} z^{-4}
$

Collect powers of the variables:

$
\frac{-5}{20} x^3 y^3 z^4 x^{-3} y^{-7} z^{-4}=\frac{-5}{20} x^{3-3} y^{3-7} z^{4-4}=\frac{-5}{20} y^{-4}=\frac{-5}{20 y^4}
$

RonL
• October 25th 2006, 09:19 PM
wpcp15
Thanx, I started that way but i made a different turn