I don't understand how to find the maximum and minimum.

Determine whether the given quadratic function has a minimum value or maximum value. Then find the coordinates of the minimum or maximum point.

15.f(x) = -x2 + 2x - 4

20.f(x) = 2x2 - 4x

19.f(x) = x2 - 2x + 1

30.f(x) = -3x2 - 3x

4 answers

#15 and #30 open downwards, so they have a maximum
#20 and #19 open upwards, so they have a minimum.

change the equations to the form
f(x) = a(x-h)^2 + k by completing the square
You should have learned how to do this, and read the vertex from that form.
what are the maximum value and minimum value of (x)=12sin(2x-2pi/3)-5l+3
2x2- 16x+4= i do not know
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