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Comment on Power of 5
ammmmmmazing videos!! loved
Thanks!
Thanks!
Hi Brent!
I stumbled a little bit in the beginning but got to the answer eventually. My question is, in an expression like the one above, would it be fair to equate 5^(3x+1) to 5^1, even with the 4 present?(Assuming that we split 20 into 5 times 4) eg:5^(3x+1) = 5^1 *4^1
Yes, that's correct.
Yes, that's correct.
If 5^(3x+1) = 20, then we can also say that 5^(3x+1) = (5^1)(4^1)
Cheers,
Brent
hi brent,
so the part where multiplied powers of both sides by 1/3. that was to eliminate 3 from 3x correct?
That's correct.
That's correct.
Our goal is to determine the value of 5^(-x), so I needed a way to eliminate the 3 from 3x.
Cheers,
Brent
Hi Brent,
In this question:
What is the cube root of w?
(1) The 5th root of w is 64.
(2) The 15th root of w is 4.
Do we really have to solve equation 1 and 2 to get the answer? Or just by looking at the equations, we know that since the 5th and 15th root of w is given, it should be possible to find the cube root of w and both equations 1 & 2 should suffice?
I want to confirm if we have to solve this to prove it or if we can just see the statements and directly choose answer D.
Your reasoning is perfect.
Your reasoning is perfect.
Since we COULD determine the actual value of w from each statement, we COULD calculate the cube root of w.
In other words, we COULD answer the target question with certainty.
Here's my full solution: https://gmatclub.com/forum/what-is-the-cube-root-of-w-136884.html#p2626640