Quick Review: Slope is… Positive Slope: Negative Slope: Steepness of a line, m, rise, change in y, common difference run change in x Positive Slope: Negative Slope: Zero Slope: Undefined Slope:

SOLVING FOR Y AND PUTTING EQUATIONS INTO Slope - Intercept Form Chapter 12-3

CONCEPT: Any linear equation can be graphed on a coordinate plane. In order to be able to graph the equation, it has to be set up properly. Doctor / surgery Driving Vacation The ONLY way to graph an equation is from slope-intercept form.

y = mx + b **Slope-intercept form: y = mx + b m is the slope and b is the y-intercept. m and b are place holders for numbers. In slope-int. form, m & b will be numbers y = mx + b Slope y-intercept

y = 6x + 2 y = − 2 3 x - 5

Slope-intercept form is how you need an equation to be so that you can EASILY graph it. Standard form is another way of seeing a linear equation, but you can’t graph it – you would have to put it into slope-intercept form.

To put any linear equation into slope-intercept form, you have to use inverse operations to solve for y.

Let’s put this equation in slope-intercept form: 5y = 3x

2x + 3y = -12

3y = 4x + 15

You must always have y, m, x, and b You must always have y, m, x, and b. This means that if an equation says y=mx, you assume that b is 0 (and add 0). y = mx + 0

Change to slope-intercept form: 4x + 3y = 9

-5x – 9x = 4y – 4 -6y – 2x = 8 7y – 7x = -4 1y – 3x = 4