Question

Use the definition of continuity to determine whether f is continuous at a.
f(x) = x - 4/x +5  a = 4
A. Not continuous B. Continuous

Answer 1

@RadEn

Answer 2

f(x) will continous at point x = a if
the value of f(a) = limit (x->a) f(x)

let's check it :
f(x) = (x - 4)/(x +5), so the value of f(4) =
f(4) = (4-4)/(4+5) = 0/9 = 0

lim (x->4) f(x)
= lim (x->4) (x - 4)/(x +5)
= (4-4)/(4+5) = 0/9 = 0

because they are same,
therefore f(x) be continous at point x = 4

Answer 3

wow thank again @RadEn

Answer 4

you're welcome :)

Answer 5

;-)