Question

What is the range of the functuon f(x)=(x-4)(x-2)

Answer 1

The range is [-1, ∞).

Explanation:

The points where the graph of this function cut the x axis are at x = 2 and x = 4 , it opens upwards and has a minimum value.

It has a minimum value when x = (2 + 4) / 2 = 3.

When x = 3, f(x) = (3 - 4)(3 - 2) = -1.

So the range is all real values of x >= -1, or [-1, ∞)