We know the equation of a line is y=mx+b where m is the slope and b is the y-intercept. Yesterday we were given the values for m and b and were asked to determine the equation of the line. Pretty straight forward. What if we were given the slope and 1 point that wasn't the y-intercept OR we were given two points on the line, could you determine the equation of the line??
Ex. 1. Determine the equation of the line that has a slope of -1/2 and passes through point A(4,1).
y=mx+b we know m=-1/2 and from the coordinates x=4 and y=1. Substitute these in and solve for b.
1=(-1/2)(4) + b
1=-2 +b
1+2 = b
b = 3
therefore y = -1/2x + 3
Ex. 2. Determine the equation of a line that passes through point A(1,4) and point B(4,-2).
We do the same thing as example one but we first have to figure out the slope by
m=y2-y1/x2-x1
Check the notes in class for full solutions.
Assigned work: pg. 350#1, 5, 7, 8, 11a
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