Indices trouble (1 Viewer)

darshil · Feb 17, 2009

i tried but could not do some questions:

Express as positive indices
1. $\frac{3^{2n} \times25^{2n-1}}{15^{n-1}}$
2. 4^-2 * 6^3 * 8^4 x 12^-2

Thanks for all the help seriously

solomarc20 · Feb 17, 2009

(3^2n x 25^2n-1) / (15^n-1)

= (3^2n x 5^(4n-2) / ((3x5)^n-1)
= (3^2n x 5^(4n-2) / ((3^n-1) x (5^n-1))
= (3^n+1) x (5^3n-1)

If the working above is not right, you need to apply your index laws to simplify the numbers down to 3s and 5s, before cancelling. I hope I'm right...

TBK11 · Feb 19, 2009

2)
4^-2 * 6^3 * 8^4 x 12^-2
Note: where the . is thats (Times) [=

lolokay · Feb 19, 2009

^except that the ^-2's have been turned into -2's

$4^{-2}\times6^3\times8^4\times12^{-2} \\ = 2^{-4}\times 2^3\times 3^3\times 2^{12}\times 2^{-4}\times 3^{-2}\\ = 2^7 \times 3\\ = 384$

darshil · Feb 20, 2009

thanks for the reply guys, im gonna ace it now

Indices trouble (1 Viewer)

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