Question 68682
what is the equation for the coordinates (1,2) and (2,4)

Two points determine a line. Given you point you can also find the equation of the line.
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1. Find the slope of the line through two points (1,2) and (2,4).
{{{m = (y[2]-y[1]/x[2]-x[1])}}}, 
Let (x1,y1) = (1,2)
<br>(x2,y2) = (2,4)
<br>{{{m = (4-2)/(2-1)}}}
{{{m = 2/1}}} or 2

<br>2.Using slope - intercept form, find y - intercept
{{{highlight (y = mx + b)}}}, Choose one point of the line (1,2) and substitute it to the equation including the slope to find the b or y-intercept.
m = 2, x = 1 and y = 2
2 = 2(1) + b
2 - 2 = b
0 = b

<br>so the slope-intercept form of the equation is y = 2x + 0
or y = 2x