Answer:
It took Shen 1 hour and 29 minutes to cook.
Direct Characterization
Step-by-step explanation:
By Geometric mean property:
The derivative of ln(u) is du / u.
d/dx (ln y) = y' / y
y=-x²-6x+7
=-(x²+6x+3²-3²)+7
=-(x+3)²+9+7
=-(x+3)²+16
axis of symmetry is x+3=0 or x=-3
vertex=(-3,16)