Question

Let f(x) = 9/x
The slope of the tangent line to the graph of f(x) at the point (-2, -9/2) is -2.25. The equation of the tangent line to the graph of f(x) at (-2, -9/2) is y=mx+b for
m = -2.25
b = ?

Answer 1

y = mx -mPx +Py

y = -2.25x +(2.25)(-2) -(9/2)

Answer 2

b = -4.5 - 9/2 = -4.5 -4.5 = -9

Answer 3

ha thanks again, man. What's the universal formula for getting the intercept? I can figure everything else out but that :/

Answer 4

well; in my universe; I use -m(Px) + Py; where; m=slope and P(x,y)

Answer 5

if you algebrate the point slope form you get this thing

y - Py = m(x - Px)

y = mx -mPx + Py; where b = -mPx +Py

Answer 6

ooohh, I was messing up on the symbols -_-

got it! cheers :]