How can I find the general form equation of a line from two points?

Question

Given the input:

double x1,y1,x2,y2;

How can I find the general form equation (double a,b,c where ax + b

Answer 1

Shortcut steps: "Problem : (4,5) (3,-7)" Solve: m=-12/1 then 12x-y= 48 "NOTE:m is a slope" COPY THE NUMERATOR, AFFIX "X" Positive fraction Negative sign on between. (tip: simmilar sign = add + copy the sign) 1.Change the second set into opposite signs, 2.ADD y1 to y2 (means add or subtract them depending of the sign), 3.ADD x1 to x2 (also means add or subtract them depending of the sign), 4.Then Multiply 12 and 1 to any of the problem set. After that "BOOM" Tada!, you have your answer