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Old 05-25-2007, 03:16 AM
Silent A Silent A is offline
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Default Re: Please help me with my homework! ( induction problem)

[ QUOTE ]
Show for n=1:

3^6+5^3=854 = 14*61 == multiple of 14

Assume for n.

Show for n+1:

3^(4(n+1)+2) + 5^(2(n+1)+1) = 3^(4n+6) + 5^(2n+3)

= 3^6 * 3^4n + 5^3 * 5^2n

= 729(3^4n) + 125(5^2n)

= 729 * 81n + 125 * 25n

[/ QUOTE ]

shouldn't this be:

= 729 * 81^n + 125 * 25^n

= (9^3)(9^2n) + (5^3)(5^2n)

it's not obvious to me how I should continue
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