Question 82844
Lines that are perpendicular have slopes that are the negative reciprocal of each other:
For example:
if slope #1 = 2, then the perpendicular slope = -1/2
.
Line #1 
4x-5y=7 [re-write in the y=mx+b format]
4x-4x-5y=-4x+7
-5y=-4x+7
-5y/-5=-4/-5x+7/-5
y=4/5x-7/5
Slope # 1 = 4/5
.
So, slope of Line #2 =-5/4 [because I flipped 4/5 and multiplied it by (-1)]
y=mx+b [plug-in the values (2, 6) and (m=-5/4) and solve for the b-term]
6=(-5/4)(2)+b
6=-5/2+b
5/2+6=b
17/2=b
Plug-in just the values of the slope and the b-term: 
y=-5/4x+17/2