1. Ms. Neal Geometry

2. In order to write an equation of a line, you will need two points: 1) Label each point (x 1,y 1 ), (x 2,y 2 ) 2) Substitute the information into the equation 3) Solve the equation Remember the formula for slope (which we learned in the previous section)? If you don’t here’s the formula.

3. Let’s consider the two points (4,3) and (-2, -1). Be sure to label all the points. Once we perform the calculations, the slope of the two points are 2/3. An easy way to find the slope is by using the rise/run method.

4. Is this what your graph looks like? If not, where did you go wrong? Have you found the slope? Did you follow the steps? Now we are ready to use the slope to find the equation of a line! Are you ready?

5. The slope we learned how to calculate in the previous sections is the same slope (m) we use for the slope intercept equation!

6. So, in order to find the slope using standard form, we use the numbers for A & B given in the equation! This is pretty simple, right? If we have an equation in standard form, we can still find the slope!

7. I want you to notice how important the slope is to finding the y-intercept. Now that we have the slope we to find our first set of points (x 1, y 1).

8. Another way to get our equation into slope- intercept form is by using the point slope method. Using Point slope form, we are going to substitute the first set of points and the slope into the equation. **Notice that we label the points (x 1, y 1 ). Please remember to substitute your numbers into the correct spots. Are you ready to check your work?

9. In order to complete the problem and get it into the y=mx+b form, you need to add 3 to both sides. Did you get the correct answer?

10. In an ordered pair, the first number is the x- coordinate. The second number is the y- coordinate. So, if we graph. (-3, 2), it would be in the quadrant II.

11. 1. (3, 1) 2. (1, 3) 3. (-3, 1) 4. (3, -1) A

12. The first quadrant contains all the points with positive x and positive y coordinates and is represented by the roman numeral I. The second quadrant contains all the points with negative x and positive y coordinates and is represented by the roman numeral II. The third quadrant contains all the points with negative x and negative y coordinates and is represented by the roman numeral III. The fourth quadrant contains all the points with positive x and negative y coordinates and is represented by the roman numeral IV.

13. PG 147-48 #2-44 (EVENS)