JEE Mains · Maths · STD 11 - 12. limits
If \(\mathop {\lim }\limits_{x \to 1} \frac{{{x^2}\,\, - \,ax\, + \,b}}{{x\, - \,1}}\,\, = \,3,\) then \(a + b\) is equal to
- A \(5\)
- B \(1\)
- C \(-4\)
- D \(-7\)
Answer & Solution
Correct Answer
(D) \(-7\)
Step-by-step Solution
Detailed explanation
\(\mathop {\lim }\limits_{x \to 1} \frac{{{x^2} - ax + b}}{{x - 1}} = 5\) \(1 - a + b = 0\,\,\,\,\,\,\,.......\left( i \right)\) \(2 - a = 5\,\,\,\,\,\,\,.....\left( {ii} \right)\) \( \Rightarrow a + b = - 7\)
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