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If (2x + a)(2x + b) = 4x^2 4x + ab, then a + b = ?
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11 May 2022, 01:45
11 May 2022, 01:45
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Question Stats:
80% (01:22) correct
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If \((2x + a)(2x + b) = 4x^2 – 4x + ab\), then a + b = ?
(A) –4
(B) –2
(C) –1
(D) 2
(E) 4
(A) –4
(B) –2
(C) –1
(D) 2
(E) 4
Part of the project: GRE Quantitative Comparison & Problem Solving Challenge
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GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GRE Math Essentials for a TOP Quant Score - Q170!!! (2021)
GRE Geometry Formulas for a Q170
GRE - Math Book
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Re: If (2x + a)(2x + b) = 4x^2 4x + ab, then a + b = ?
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11 May 2022, 06:16
11 May 2022, 06:16
2
Carcass wrote:
If \((2x + a)(2x + b) = 4x^2 – 4x + ab\), then a + b = ?
(A) –4
(B) –2
(C) –1
(D) 2
(E) 4
(A) –4
(B) –2
(C) –1
(D) 2
(E) 4
Given: \((2x + a)(2x + b) = 4x^2 – 4x + ab\)
Expand the left side: \(4x^2 + 2xb + 2xa + ab = 4x^2 – 4x + ab\)
Subtract \(4x^2\) from both sides of the equation: \(2xb + 2xa + ab = –4x + ab\)
Subtract \(ab\) from both sides of the equation: \(2xb + 2xa = –4x\)
Factor the left side: \(2x(b + a) = –4x\)
Divide both sides by \(2x\) to get: \(b + a = –2\)
Answer: B
Re: If (2x + a)(2x + b) = 4x^2 4x + ab, then a + b = ?
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22 Jan 2024, 12:19
22 Jan 2024, 12:19
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