Question 58685
WHAT YOU HAVE (X1,Y1)(X2,Y2) IS USED TO CALCULATE THE SLOPE THUS
(Y2-Y1)/(X2-X1)
(5-(-2))/(12-(-9))
(5+2)/(12+9)
7/21=1/3 IS THE SLOPE (THE LINE IS A LEFT TO RIGHT LINE (+ SLOPE) AND RISES 1 SQUARE FOR EVERY 3 SQUARES TO THE RIGHT.
THE FORMULA FOR THIS LINE IS FOUND BY FINDING THE Y INTERCEPT BY SETTING REPLACING THE X & Y UNKBNOWNS BY ONE OF THE POINT COORDINATES.
THUS
-2=1/3(-9)+b
-2==-9/3+b
-2=-3+b
-2+3=b
b=1
THUS THE EQUATION IS
Y=1/3X+1