Description
Explanation & Answer
f(x) - f(a) / x - a
f(x) = x^2 - 4x + 5 a = - 2f(a) = (a)^2 - 4(a) + 5
= a^2 - 4a + 5
Now putting the values in the above relation , we get
f(x) - f(a) / x - a = (x^2 - 4x + 5) - (a^2 - 4a + 5) / x - a
= x^2 - 4x + 5 - a^2 + 4a - 5 / x - a
= x^2 - a^2 - 4x + 4a + 5 - 5 / x -a
= (x - a)(x+a) - 4(x + a) / x -a
Hence
f(x) - f(a) / x - a = (x - a)(x+a) - 4(x + a) / x -a