Notice that in the chart, the 2 grey sections (slope and y-intercept) are the two numbers that we need in order to write our equation.
(CHART #1)
We know the slope and a point (x,y). We can use this information to solve for b. Then we can write our equation.
First we will substitute the information that we know (that is in our chart) into the equation, y = mx + b. Then you will solve for b. (CHART #2)
Now we know the slope (m) is -2 because that was given to us. We also now know the y-intercept (b), which is 9 because we just solved for b.
We can now write our equation!
m = -2
b = 9
y = mx + b
y = -2x + 9
