5x+8y= -9 re-arrange in to y= mx + b form
8y = -5x - 9
y = -5/8 x - 9/8 shows m1 (the slope) = =5/8
Remember how to find pepindicular slope?
- 1 / m1 will be perpindicular -1 / (-5/8) = 8/5
so the line we are looking for is y = 8/5 x + b Now sub in the point given (10,10) to find the value of b
10 = 8/5 (10) + b b = -6
your line is y = 8/5 x - 6 m+ b = 8/5-6 = - 4 2/5