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If y^2 + xy - 3x = 9, and dy/dt = -2 when x = 2 and y = -5, what is dy/dt when x = 2 and y = -5?

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Final answer:

To solve for dy/dt when x = 2 and y = -5, differentiate the given equation using implicit differentiation and substitute the given values to solve for dy/dt.

Step-by-step explanation:

To find dy/dt when x = 2 and y = -5, we need to differentiate the given equation with respect to t using implicit differentiation.

Start by taking the derivative of each term:

  • d(y^2)/dt = 2y * (dy/dt)
  • d(xy)/dt = x * (dy/dt) + y * (dx/dt)
  • d(-3x)/dt = -3 * (dx/dt)
  • d(9)/dt = 0

Now substitute the given values to solve for dy/dt:

2(-5) * (dy/dt) + 2 * (-2) + (-3) * 0 = 0

-10(dy/dt) - 4 = 0

-10(dy/dt) = 4

dy/dt = 4/-10 = -2/5

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