3b)
y'' = -2x
Integrating,
y' = -x^2 + C
When f'(x)=0 (min turning point) x= 3
0=-9 + C
C= 9
Therefore, y' = -x^2 +9
Integrating,
y= -x^3/3 +9x + C
When x=3, y = 7
7 = -9 + 27 + C
C = -11
Therefore, y=-x^3/3 + 9x - 11
Is that the correct answer? Tell me if I did something wrong