Point slope form
Point-slope form is a way to write linear equations given by the equation:
y - y1 = m(x - x1),
where m is the slope of the line, (x1, y1) is a point on the line, and (x, y) is any other point on the line.
Notice that point-slope form is more or less a rearranged form of the slope formula.
The reason we use x and y instead of x2 and y2 is that in the slope formula, we were solving for m by using two points, but hwen we are using point-slope form, we are writing a linear equation, so x and y need to be there in the final equation.
Given two points, you can write an equation in point-slope form:
|(x, y)||(x1, y1)|
|(-5, 3)||(3, 7)|
See also slope.