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:
100 red bricks
Step-by-step explanation:
Let's say red bricks is equal to 5x
Gray bricks is equal to 2x
We have an equation
2x + 5x = 140
= 7x = 140
Divide through by 7 to get the value of x
X = 140/7
X = 20
Red bricks = 5(x)
= 5(20)
= 100
Gray bricks = 2(x)
= 2(20)
= 40
Therefore in conclusion the number of red bricks is 100.
Answer:
-10x+2
Step-by-step explanation:
22-5(2x+4)
22-10x-20
2-10x
-10x+2
B.) 10x-5 is equivalent to 6x – 5 + x + 3x