JEE Mains · Maths · STD 12 - 1. relation and function
Let \(f ( x )\) and \(g ( x )\) be two real polynomials of degree \(2\) and \(1\) respectively. If \(f ( g ( x ))=8 x ^{2}-2 x\), and \(g(f(x))=4 x^{2}+6 x+1\), then the value of \(f(2)+g(2)\) is
- A \(18\)
- B \(28\)
- C \(38\)
- D \(48\)
Answer & Solution
Correct Answer
(A) \(18\)
Step-by-step Solution
Detailed explanation
\(f \left( g ( x )=8 x ^{2}-2 x \right.\) \(g\left(f(x)=4 x^{2}+6 x+1\right.\) So, \(g ( x )=2 x -1\) \(g(2)=3\) \(f ( x )=2 x ^{2}+3 x +1\) \(f(2)=8+6+1=15\) Ans. \(18\)
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