3. x 2 is positive

5. A square number is always positive
unless it’s zero.

8. x
4(x+2)2 -38 y

10. Rewrite y=2x2-12x+25 by completing the square.
What is the minimum value of this quadratic function?
Y=2(x-6)^ (6,4)

11. Your friend tried to rewrite y=1.4x2+5.6x+3 to find its minimum value.
Explain his mistake, then find the minimum value of the function.
y=1.4 (x2 +4x )+3
y=1.4(x2+4x+4)+3-4
y=1.4(x+2)2-1

12. The number of bacteria in a refrigerated
food is given by N(T)=20T2-20T+120
for -2<T<14 where T is the temperature of
food in Celcius. At what temperature will
The number be minimal?

13. Rewrite each function to find its minimum value by completing the square.
y=2x2-8x+6
y=4x2-20x+7