Answer:
A
Step-by-step explanation:
We have the equation:

Take the derivative of both sides with respect to x:
![\frac{d}{dx}[x^2+xy-3y]=\frac{d}{dx}[3]](https://tex.z-dn.net/?f=%5Cfrac%7Bd%7D%7Bdx%7D%5Bx%5E2%2Bxy-3y%5D%3D%5Cfrac%7Bd%7D%7Bdx%7D%5B3%5D)
Implicitly differentiate:

Solve for dy/dx:

Divide:

To find dy/dx at (2, 1), substitute 2 for x and 1 for y. So:

Hence, our answer is A.
Answer:a rational number is a number that can be expressed as the quotient or fraction p/q of two integers, a numerator p and a non-zero denominator q. Since q may be equal to 1, every integer is a rational number.
Step-by-step explanation:
Answer:
Step-by-step explanation:
A horizontal cross section of a cone will be circle
We are trying to find miles/hour, which shows that we are going to be dividing the total number of miles by the total number of hours. Thus, in this case, the miles/hour rate will be:

He drove 40 miles in one hour.