Algebra 07.27.13

Yesterday we learned a bit about slope and how horizontal lines will always have a slope of zero because if you divide zero by any number it is still zero. This brings us to vertical lines, these lines have a change in x of zero, because we can't divide by zero the slope of any vertical line is undefined. Given two points (x₁, y₁) (x₂,y₂) we can then find the slope using this equation where "m" stands for slope, m=(y₁-y₂)/(x₁-x₂). So how do we find the graph or visual representation of a line from this information? We use the slope of a line and a point on the line, we can also represent a line using slope-intercept form. This uses the slope and the y intercept to represent a line or y=mx+b where again m is slope and b is the value of y at the y intercept. We can also use point-slope form y-y₁=m(x-x₁) where (x₁, y₁) is any point on the line. If we solve for y we can convert point-slope form to slope-intercept form.