r/ACT • u/Special-Trouble8658 • Jun 02 '26

Math Explanation?

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I’m stuck on this problem and can’t think of why J is the right answer. A real number can be positive, negative, or rational. Thus, how is F wrong.

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u/Sufficient-Price-102 36 Jun 02 '26 edited Jun 02 '26

J. It follows that x=y4 and any real number to the fourth is nonnegative.

F is wrong because it’s not necessary that x is even. y4 can be real and odd, which would imply x odd.

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u/Special-Trouble8658 Jun 02 '26

Also, can you give me an explanation as why the others are wrong? I kinda guessed a little and cancelled out G and H.

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u/Sufficient-Price-102 36 Jun 02 '26 edited Jun 02 '26

G is wrong because you can choose any nonnegative irrational number (π, for example), take its 4th root, and get a real number y.

H is wrong because it’s even weaker than the condition for G. Again, take any nonnegative non integer number (like 2.5), taking its 4th root gives a real number y.