Step-by-step explanation:
How you find the slope of a straight line, depends on what information you are given. Here are some pieces of information you might be given and how to find the slope in each:
<u>two random points</u>
* Use the formula for slope and substitute each of the x and y values.
Ex: given points (1,2) and (3,4)
<u>picture of the graph</u>
* You can choose two random points on the graph and do <u>two random points</u> method
* OR you can use another formula for slope: m = rise/run
First, choose two random points on the graph that are on the grid lines. Count distance between first and second point. (The first point being on the left side.)
- Count how far away the two points are vertically. This number is "rise". If the second point is under the first point, the rise is a negative number.
- Count how far away they are horizontally. This is the "run". This number will not be negative.
Divide the number for rise by the number for run to get the slope.
<u>random point and the y-intercept</u>
* Use slope-intercept form and substitute the random point and the y-intercept
y = mx + b
Substitute the y-coordinate of the point for y, the x-coordinate of the point for x, and the y-intercept for b.
Isolate m to find the slope.
Ex: given (2,1) and y-intercept (0, 0)
y = mx + b
1 = m2 + 0
1 = 2m
m = 1/2