A line through the points (2, -9) and (j, 17) is parallel to the line 2x + 8y = 21. What is the value of j?
2x + 8y = 21
8y = -2x + 21
y = ( -2/8)x + 21/8
y = (-1/4)x + 21/8
Slope = -1/4
So
(17 - -9 ) 1
________ = - _____
( j - 2) 4
26 / ( j -2) = -1/4 cross-multiply
4 * 26 = -1 ( j -2)
104 = 2 - j
j = 2 - 104 = -102
