# Thread: [SOLVED] Algorithm for solving 2 equations, 2 unknowns

1. ## [SOLVED] Algorithm for solving 2 equations, 2 unknowns

Anyone have an algorithm for solving a simple 2 equations, 2 unknown problem?
How do you do unknowns in an equation? It seems like you need a parser, substituter and reducer.

The equation(s) is y = ax + b (a straight line) where x and y are known for two points on the line. How do you find the values of a & b?

For example:
Given the points: pt1= 1,0 and pt2= 3,1
equation1 = 0 = a*1 + b
equation2 = 1 = a*3 + b

How do you write a program to solve for the values of a and b?

Also posted at CodeGuru Forums - Algorithm for solving 2 equations, 2 unknowns

Thanks,
Norm

A bit rusty with algebra:

slope = (p2.y - p1.y) /(double) (p2.x - p1.x);
intercept = p1.y - slope * p1.x;
Last edited by Norm; 08-24-2008 at 08:31 PM.

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