Maths help needed !!?

KEY STEPS FOR SOLVING WORD PROBLEMS

state the problem in your own words, deciding which value or values are known.

choose a variable or variables to represent the unknown(s), using the facts from the given problem.

Draw a diagram, use a formula, create a table, or use any other strategy that will help you write an equation for the situation given in the problem

Solve the equation for the unknown value(s)

interpret your results according to the facts given in the problem by substituting the values you have found for the variables into the original equation.

Write your final answer as a complete sentence.

f ` (x) = - 4 / x²

f ` (-8) = - 4 / 64 = - 1 / 16 = m

y + 1/2 = (-1/16) [ x + 8 ]

y = (-1/16) x - 1

think about what the point-slope form means:
y-b=m(x-a)
(a,b) is a point, m is the slope @ some point
so you have the point (-8, -1/2), to find the slope, recall that derivative @ a point is the slope @ that point
so now you can write in point-slope form, or write in slope-intercept from y=mx+c, plug-in the point to find c