Slope intercept- form- y=mx+b

Standard- Form- ax+by=c

point-slope- Form- Y-Y1=M(X-X1)

How to find the slope?

Y2-Y1

-------

X2-X1

ex. How to find the slope with the points (2,4) and (1,4)

4-4        0

-----  = ---- = 0

1-2       -1

Ex Write the equation of the line with slope -2 that passes through the point (-1,7) in point slope form.

a.) y-7=-2(x+1)      b.)   y+7=-2(x-1)

        correct                     incorrect

Why is b incorrect?

because the points +,- sign wasn't switched.

Ex. Write y=3x-2 in standard form using integers.

-3x+y=-2

remember to change the signs when moving the integer to the other side of the = sign.

What are the slope and y-intercept of y=3x-5

the slope is 3 and the y-intercept is -5.

To graph this equation would look like this(below).

To graph an equation in standard form with the equation 2x+3y=12 all you have to do is 2x=12 and get x=6 and then do the same with 3y=12 and getting y=4 which comes to (6,0) and (0,4) and then graphing the points.

To write linear equations u have to find the rates of change for consecutive ordered pairs on a table. What your trying to find out is whether the relationship is linear or not.

to find out if it is linear or not you have to find the difference between 8 and 4.5 then 4.5 and 3 and so on and then you do the same with the temperature. After finding the diffrences you take the difference of 197.6 and 203.9 and put it over the difference of 8 and 4.5 like this 6.3  then do the same with the rest of the numbers in the table and divide the difference of the temperature over the altitude

       ----  and see if all the differences are the same if they are then the relationship is linear if not then the relationship is not linear.

      -3.5  

If the relationship is linear then take the number that you got from dividing the differences and take a point from the table for example like (8,197.6) and then put it in point slope form and then put it in slope-intercept form and that will be your answer. If the relationship is not linear then you don't have to do anything after that.