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Question for sibbineni and others

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by LSB » Tue Aug 05, 2008 6:17 pm
Posted this in the wrong forum

In the below post (see link) this manipulation was performed

5^21 * 4^11 = 2 * 10^n

5^21*2^22=2 * 10^n

is there any specific rule around doing this? Thank you

https://www.beatthegmat.com/algebra-question-t15392.html
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Source: — Problem Solving |

by Neo2000 » Tue Aug 05, 2008 6:42 pm
Law of Exponents

a^m * a^n = a^(m+n)

In this case we could re-write 4 as 2^2


Again, according to law of exponents

(a^m)^n = a^(m*n)

Can you do it from here??
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by LSB » Tue Aug 05, 2008 6:46 pm
WOW - I have been looking at this stuff for too long. I knew both of the laws but couldn't clou in on this one if you had held a gun to my head :-)

Thanks Neo
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by Neo2000 » Tue Aug 05, 2008 6:50 pm
LOL! we all have our days! I remember in one Sets problem i was struggling with, I couldnt for the life of me figure out why 70+40 did NOT equal 100. :lol:
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