1/11/010

Today in class, we learned about slope-intercept. Slope-intercept uses the formula:
y=mx+b
where:
m=slope
b=y-intercept.
For example, in the equation y=4x+6:
m=4 and b=6.
y=mx+b
y=4x+6
If you are given a slope: .5 and a y-intercept: 7,
you would use that to write the equation y=.5x+7.
Say you are given 2 points on a graph: (0,3) and (5,-2). You use y1-y2/x1-x2 for the slope: -2-3/5-0=-5/5. So, the slope is -1. You know the y-intercept is 3 because of the point (0,3) so the equation is y=-1x+3.
To graph an equation, y=4x+2, for example, start with x being 0. the y-intercept is 2, so your first point is (0,2). the slope is 4, so either use 4/1 for graphing other points or substitute x for whatever number and solve for y to graph the other (x,y)s.