Explain how you know that x^2-8x+20 is always positive.
Please help.

Answer:
if you rearrange to complete the square, you get (x^2-4)^2 +4
and seeing as anything squared will always be positive or zero, the lowest possible value for (x^2-4)^2 is 0, when x = 4
and 0 + 4 = 4, which is greater than 0, so positive
Step-by-step explanation: