Differentiating both sides of

with respect to <em>x</em> yields (using the chain rule)

Solve for d<em>y</em>/d<em>x</em> :

The answer is then D.
Well since there is five people the answer is 40$.
2(b+3) = 2
2b + 6 = 2 ( -6 )
2b = -4 ( / 2)
b = -2
0.47 is the answer. Because it's in the middle of 0.43 and 0.50. I answered this on your last question =p
The answer is x=1/2 or 0.5