find the maximum and/or minimum values of the function f(x) for the indicated value of x
f(x)=x^2 -4x+3 2<_ x _>5
what you mean is
2 <= x <= 5
This is just a parabola, with vertex at (2,-1).
So, clearly, f(2) = -1 is the minimum value.
The axis of symmetry is at x = 2, so f(5) will be the max on the interval [2,5], since it is away from the axis.