Help.

(-2, 15)   ( 9 , - 18)

Slope  =    [   -18  - 15  ]                    -33

                ___________     =            ____       =    - 3

                 [ 9   -   -2     ]                     11

To  write the equation  using   ( -2 , 15)    we have 

y  = slope ( x  -  x coordinate)   +  y coordinate   

y  =  -3 ( x -  -2 )   + 15          simplify

y  = -3 ( x + 2)  +  15      subtract 15 from both sides

y - 15 =  -3(x + 2)                 

Note, NSS....either point could have been used....it would have produced a different looking equation....but....when both were simplified, they would be EXACTLY the same.....!!!

Poiint   ( 8 , -8)  slope 3

y  = slope ( x  - given x coordinate)  +  (given y coordinate)

y  = 3  ( x  - 8)   +  ( - 8)    simplify

y =   3 ( x - 8)   - 8     add 8 to both sides

y +  8   =  3 ( x - 8)