A line passes through the points (-3,-5) and (6,1). This line is the graph of the equation Ax + By = C, where A, B, and C are integers with greatest common divisor 1, and A is positive. Find A + B+ C.
(2, -8, and -4 are wrong...)
The slope of this line =
[ 1 - - 5 ] / [ 6 - - 3 ] = 6 / 9 = 2 / 3
So...using either point.......the equation of the given line is
y = ( 2/3) ( x - 6 ) + 1 multiply through by 3
3y = 2 ( x - 6) + 3
3y = 2x - 12 + 3
3y = 2x - 9 rearrange as
2x - 3y = 9
A = 2 B = -3 C = 9
A + B + C = 8