How to Write Linear Equations

Just a preview of Slope-Intercept form… y = mx + b y: y-value of a point m = slope x = x-value of a point b = y-intercept I am showing you this because this is how your equations will look when you write them using given points in a table!!

Vocabulary preview… Slope (m): Y-intercept (b): The steepness of a line Y-intercept (b): Where the line crosses the y-axis on the graph

How to write an equation from a table… 1. Look for the change in the y-values on the table. (the pattern) 2. Take this number and write it in front of the x in the y=mx+b. 3. Take an x-value from the table and plug it in, and multiply your two numbers. 4. Find out how much you have to add or subtract to reach the y-value matched to that x-value you used. Look at the example on the next slide 

Example Look at the pattern in the y’s. It is +3. Take this and start writing your equation. Y = 3x Now take a value and plug it in for x. Start with 0. Y=3*0, which is just 0 Well, that equals zero, right?! So, if you look at the y-value that is matched with the x-value you just used it is 3, not 0! So what do you have to add or subtract to get from 0 to 3?? You have to add 3!! So your equation is now… Y= 3x +3!! X Y 3 1 6 2 9 12