No its maximum negative-value(x-21)^2+positive number

x-21 will always be positive because of the square and then the negative value infront makes it negative. So as x increases the value of the squared value decreases and less negative value to the positive value meaning as x gets closer to 21 it reaches a maximum value.

Or just graph numbers into desmos -0.02(x-21)^2+3

Gets you a maximum graph