Question

For the equation xy + 4x + 7y = −4, calculate the derivative dy/dx at the point (1, −1).

Answer 1

x*(dy/dx)+y + 4 + 7(dy/dx) = -4
Plug in x = 1, y = -1
(dy/dx) - 1 + 4 + 7(dy/dx) = -4
8(dy/dx) = -7
dy/dx = -7/8

Answer 2

Bahroom do you care to help me all I have left is 2 more?

Answer 3

Sorry for interupting

Answer 4

its -3/8

Answer 5

then i probably added or subtracted wrong. just check the arithmetic... oh yea the derivative of a constant is 0, so:
x*(dy/dx)+y + 4 + 7(dy/dx) = 0
(dy/dx) - 1 + 4 + 7(dy/dx) = 0
8(dy/dx) = -3
dy/dx = -3/8

Answer 6

thanks man!