y=4−9xy = 4 - 9xy=4−9x
dydx=ΔyΔx=−9\frac{dy}{dx} = \frac{\Delta y}{\Delta x} = -9dxdy=ΔxΔy=−9
Δy0.1=−9 ⟹ Δy=−9×0.1=−0.9\frac{\Delta y}{0.1} = -9 \implies \Delta y = -9 \times 0.1 = -0.90.1Δy=−9⟹Δy=−9×0.1=−0.9
