Question

How do I find the x intercept and y intercept by the function f(x) = 400 - 4/5x?

Answer 1

To find the x intercept, set y = 0, then solve for x:

Remember y = f(x) so you have
y = 400 - (4/5)x

Set y = 0
0 = 400 - (4/5)x

Add (4/5)x to both sides:

(4/5)x = 400

Multiply both sides by (5/4)
x = (5/4)(400)
x = (5)(100)
x = 500

Answer 2

To find the y-intercept, set x = 0, then solve for y.