Question

Given that function
f(x) = 9, x<4
2x+1, 4≤x<12
7x-4, x≥12
Is the function continuous
a) as x tends to 4?
b) as x tends to 12?

Answer 1

look continuous to me

notice you have the straight line y = 9 as long as x < 4
at x ≥ 4 the line y = 2x+1 takes over all the way to x < 12
As soon as x reaches 12, the baton is passed to y = 7x - 4

Answer 2

at x = 12
2x+1 = 25
7x-4 = 80