snickelfrix wrote:If k^1/3= k/4 and k doesn't = 0, then when is the value of k^2?
(A) 2
(B) 7
(C) 8
(D) 16
(E) 64
I was told the answer is 64 but I got 8. Do I fill in k with a random value?
We can PLUG IN THE ANSWERS, which represent the value of k².
The correct answer choice is probably a perfect square, which will yield an integer value for k.
Of the 5 options, only D and E are perfect squares.
D: k²=16
Here, k=±4.
Plugging k=4 into k^(1/3) = k/4, we get:
4^(1/3) = 4/4
4^(1/3) = 1.
Doesn't work.
Plugging k=-4 into k^(1/3) = k/4, we get:
-4^(1/3) = -4/4
-4^(1/3) = -1.
Doesn't work.
Eliminate D.
E: k²=64
Here, k=±8.
Plugging k=8 into k^(1/3) = k/4, we get:
8^(1/3) = 8/4
2 = 2.
Success!
The correct answer is
E.
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