Help with functions!!!

Question

How can you find the least possible value of a function? In these problems, I'm supposed to find the value of x for which the least value occurs.

 

Example questions I'm trying to solve:

a(x)=x^2  and   b(x)=(x-1)^2

Answer 1

x² ≥ 0, so the least value for a(x) is zero.

 

(x - 1)² ≥ 0, so the least value for b(x) is zero.