Expert: Lynn Houston - 5/16/2009

Question
Write and equation of the line containg the given point and perpendicular to the given line (8-7);6x+5y=7

Answer
Write and equation of the line containg the given point and perpendicular to the given line (8, 7);6x+5y=7

Start by putting the eq in slope intercept form y = -6/5x+7/5

a perpendicular line has a negative inverse slope of the line given, so the slope for the new line would be 5/6.  Now you have the slope and two points, so you just need to find the y intercept of the new line.  To do that, use the eq y = mx+b and solve for b.  
7 = 5/6(8) + b
7 = 40/6 + b
b = 2/6 = 1/3

so the eq of the line containing the pt (8, -7) and perpendicular to 6x+5y = 7 is

y = (5/6)x + (1/3)

This is assuming that you incorrectly used a dash in the coordinates instead of a comma and the points are actually 8 and 7 and not 8 and -7.  Otherwise, the problem doesn't work out.

If it is in fact -7, then the answer is not quite as neat.  y intercept would be -41/3 and the eq would be y = 5/6x - 41/3