let's say the bill without the tip is "x" amount, so that'd be the 100% of the bill, but we also know that 4.50 is the 18% of "x".
so if 4.50 is the 18% of "x", how much is "x"?

The vertex is when x=0, so (0, 2) is the answer.
Answer: My answer would be 2
Simplify
f(x) = 3 + 11
Multiple
fx = 3x + 11
<span>Solving for variable 'f'.
Move all terms containing f to the left, all other terms to the right.
Divide each side by 'x'.
f = 11x-1 + 3
Simplifying
f = 11x-1 + 3
Reorder the terms:
f = 3 + 11x<span>-1</span></span>