NDA Math Sets Relations and Functions

Concept:
To get the value of any function at any point with respect to some other function, we need to manipulate the given function/ point in such a way that we get the function that is needed.
Calculation:
Given, f(x+1)=x2−3x+2
‌‌=x2−2x−x+2
‌‌=x(x−2)−(x−2)
‌‌=(x−2)(x−1)
‌‌=(x+1−3)(x+1−2)
∴f(x)=(x−3)(x−2)
=x2−3x−2x+6
=x2−5x+6