Finding an x and Y intercept with two points? - Answers

Given two points on a graph with coordinates of X1,Y1 and X2,Y2, the slope of a straight line through the two points can be calculated as m=(Y1-Y2)/(X1-X2) The equation for the line can then be written as Y=mX+k, where k is some constant number. Note that m will be positive for lines that slant up from left to right, and negative for lines that slant up from right to left. Once m is known, k can be found by substituting the values of X1 and Y1 into the equation and solving for k. When k is known, the value of the X axis intercept can be found by setting X to zero and solving the equation for Y. The Y axis intercept value can be found by setting Y to zero and solving for X. Example: Let x1,Y1=6,4 and X2,Y2=2,2 Solve for m: m=(4-2)/(6-2)=2/4=1/2 Solve for k: Y=mX+k, 4=(1/2)6+k, k=4-3=1 If X=0, Y=(1/2)0+1=1 this is the Y axis intercept point If Y=0, 0=(1/2)X+1, 1/2X=-1, X=-2, this the X axis intercept point