Answer:
a) [tex]\frac{dy}{dx} = -27[/tex], b) [tex]m = -27[/tex]
Step-by-step explanation:
a) The instantaneous rate of change is:
[tex]\frac{dy}{dx} = 8\cdot x + 5[/tex]
[tex]\frac{dy}{dx} = 8\cdot (-4)+5[/tex]
[tex]\frac{dy}{dx} = -27[/tex]
b) The slope of the tangent line is equal to the instantaneous rate of change found previously.
[tex]m = -27[/tex]