Find a if the point (3,a) is on the line that passes through (-2,7) and (5,-8).
+128475 The slope of the line is
[ -8 - 7 ] / [ 5 - -2 ] = -15 / 7
Since ( 3, a) is on the line....we can solve fro "a" thusly
[ 7 - a ] / [ -2 - 3 ] = -15/7
[ 7 - a ] / - 5 = -15/7 multiply through by -5
7 - a = 75/7 rearrange as
7 - 757 = a
(49/7) - (75/7) = a
-26/7 = a
+36916 it is
from -2 to 5 is a distance of 7 we want 5/7 of this to get to 3 (from 2)
for a from 7 to -8 is a 'distance' of -15 5/7 * (-15) added to 7 = -75/7 + 7 = - 26/7 ( as Chris found ....!)
