Question

find dy/dx if x=-4at and y=9t^3-1​

Answer 1

$x = - 4at \\ \frac{dx}{dt} = - 4a \\ y = 9 {t}^{3} - 1 \\ \frac{dy}{dt} = 27 {t}^{2} \\ \frac{dy}{dx} = \frac{dy}{dt} \times \frac{dt}{dx} \\ = \frac{27 {t}^{2} }{ - 4a}$