Respuesta :
If you complete the square you get
[tex]{(x - 4) }^{2} + 4[/tex]
and as any number squared is positive and 4 is positive, the result must be positive
Answer:
x^2-8x+20=x^2-2*x*4+4^2+4=(x-4)^2+4
so (x-4)^2 is positive or zero (but +4 is always positive)
Step-by-step explanation: