Answer:
3.2
Step-by-step explanation:
x² + xy = 20
Take the derivative with respect to time:
2x dx/dt + x dy/dt + y dx/dt = 20
(2x + y) dx/dt + x dy/dt = 20
Given x = -5, y = 1, and dx/dt = -4:
(2(-5) + 1) (-4) + (-5) dy/dt = 20
(-10 + 1) (-4) − 5 dy/dt = 20
36 − 5 dy/dt = 20
5 dy/dt = 16
dy/dt = 3.2
