If x varies directly as y, then which of the following is/are correct?
I. (x² + y²) varies directly as y².
II. (x³/y⁴) varies directly as y.
Select the answer using the code given below:
A.I only✓ Correct
B.II only
C.Both I and II
D.Neither I nor II
Explanation
If x varies directly as y, then x = ky for some constant k. Then x² + y² = k²y² + y² = (k²+1)y², which varies directly as y². So I is correct. For II: x³/y⁴ = k³y³/y⁴ = k³/y, which varies inversely as y, not directly. So II is incorrect. Only I is correct.
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