You need to find the slope too.

point slope formula y - y1 = m(x - x1)
use (0, -3)
y - (-3) = 1 (x -0)
y + 3 = 1x
Hi,
The total amount is 17.91608
How I got my answer:
100 + tip%/100 * 14.56 = amount with tips
100 + 15/100 * 14.56
115/100 * 14.56
1.15 * 14.56 = 16.744
100 + tax%/100 * amount with tips = total amount
100 + 7/100 * 16.744 = total amount
107/100 * 16.744
1.07 * 16.744
17.91608 = total amount
Hope this Helps you.
True, In Euclidean geometry an equilateral triangle must be a 60-60-60 triangle.
Hope This Helps!!!
The answer to that question is 250.