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SSC Selection Post 2023 PYQ — Question 58

SSC Selection Post - Graduation Level - 27 June 2023 - Shift 4 • Quantitative Aptitude • Q58

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If 2xx+2+12x+4−12−x2x2+4x=a+bx\frac{2x}{x + 2} + \frac{1}{2x + 4} - \frac{12 - x}{2x^2 + 4x} = a + \frac {b}{x}, where a and b are integers, then the value of ab = ________ .

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Correct answer: B

Explanation

The correct answer is option 2 i.e. -6.

2xx+2+12x+4−12−x2x2+4x=a+bx\frac{2x}{x + 2} + \frac{1}{2x + 4} - \frac{12 - x}{2x^2 + 4x} = a + \frac {b}{x}

⇒ 2x2+x−6x(x+2)=a+bx\frac{2x^2+x-6}{x(x+2)}=a+\frac{b}{x}

⇒ (2x - 3)/x = (ax + b)/x

Here, a = 2 and b = - 3

ab = 2(-3) = - 6