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Which of the following must be even ?
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02 Apr 2024, 23:44
02 Apr 2024, 23:44
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Question Stats:
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Which of the following must be even ?
A. \(x^2+6x+9\)
B. \(x^2+7x+12
\)
C. \(x^2+4x-21\)
D. \(x^4+4x-12\)
E. \(x^2+8x+15\)
A. \(x^2+6x+9\)
B. \(x^2+7x+12
\)
C. \(x^2+4x-21\)
D. \(x^4+4x-12\)
E. \(x^2+8x+15\)
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Re: Which of the following must be even ?
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11 May 2024, 19:59
11 May 2024, 19:59
1
With number property questions such as these, I "plug in" even and odd into the formulas.
odd*odd = odd, odd*even = even, even*even = even
and odd+odd = even, odd+even = odd, and even+even = even
e = even, o = odd
A)
x is even: \(e^2 + 6(e) + 9 = e + e + o = o\)
x is odd: \(o^2 + 6(o) + 9 = o + e + o = e\)
B)
x is even: \(e^2 + 7(e) + 12 = e + e + e = e\)
x is odd: \(o^2 + 7(o) + 12 = o + o + e = e\)
C)
x is even: \(e^2 + 4(e) - 21 = e + e - o = o\)
x is odd: \(o^2 + 4(o) - 21 = o + e - o = e\)
D)
x is even: \(e^4 + 4(e) - 12 = e + e - e = e\)
x is odd: \(o^4 + 4(o) - 12 = o + e - e = o\)
E)
x is even: \(e^2 + 8(e) + 15 = e + e + o = o\)
x is odd: \(o^2 + 8(o) + 15 = o + e + o = e\)
odd*odd = odd, odd*even = even, even*even = even
and odd+odd = even, odd+even = odd, and even+even = even
e = even, o = odd
A)
x is even: \(e^2 + 6(e) + 9 = e + e + o = o\)
x is odd: \(o^2 + 6(o) + 9 = o + e + o = e\)
B)
x is even: \(e^2 + 7(e) + 12 = e + e + e = e\)
x is odd: \(o^2 + 7(o) + 12 = o + o + e = e\)
C)
x is even: \(e^2 + 4(e) - 21 = e + e - o = o\)
x is odd: \(o^2 + 4(o) - 21 = o + e - o = e\)
D)
x is even: \(e^4 + 4(e) - 12 = e + e - e = e\)
x is odd: \(o^4 + 4(o) - 12 = o + e - e = o\)
E)
x is even: \(e^2 + 8(e) + 15 = e + e + o = o\)
x is odd: \(o^2 + 8(o) + 15 = o + e + o = e\)
gmatclubot
Re: Which of the following must be even ? [#permalink]
11 May 2024, 19:59
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