Question

How do we know when to use y-b=m(x-a) formula and when to use y=mx+c formula?

Answer 1

Step-by-step explanation:

Both of theses equations are exaclty equal. Aby equation of the from y-b = m(x-a) can always be rewritten in the form y = mx + c and vice versa. y = mx + c is the one to use if you know (0, c) is on the line. It's just a special case of y - b = m(x - a) where the known point (a, b) happens to be (0, c).