Given two lines whose equations are 3x + y - 8 = 0 and -2x + by + 9 = 0, determine the value of b such that the two lines will be perpendicular.
How do I do this problem?
Rearrange the first equation as y = -3x + 8
Rearrange the second equation as y = (2/b)x + 9/b
Slope of first line = -3
Slope of a perp line = 1/3
1/3 = 2/b cross-multiply
b = 3*2
b = 6