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KCET · Maths · Functions

If \(f(x)=a x+b\), where \(a\) and \(b\) are integers, \(f(-1)=-5\) and \(f(\beta)=3\), then \(a\) and \(b\) are respectively

  1. A \(2,-3\)
  2. B 0,2
  3. C 2,3
  4. D \(-3,-1\)
Verified Solution

Answer & Solution

Correct Answer

(A) \(2,-3\)

Step-by-step Solution

Detailed explanation

Given, \(f(x)=a x+b\), where \(a\) and \(b\) are
integers, \(f(-1)=-5\) and \(f(3)=3\)
We have, \(f(x)=a x+b\)
Put, \(x=-1\) in above equation, we get
\(\begin{aligned} f(-1) & =a(-1)+b \\ -5 & =-a+b\end{aligned}\)
Now, \(f(3)=3\)
\(3=3 a+b\)
From Eqs. (i) and (ii), we get
\(a=2, b=a-5=2-5=-3\)