Answer:
y=8x-13
Explanation:
When you're finding a perpendicular line, you take the opposite of the slope. The slope in this equation is 1/8, so a perpendicular line will have the slope of 8. So we already know y=8x+b.
Plug in your x and y values from the ordered pair and you get -5=8(1)+b. 8×1 is just 8, so it's -5=8+b. Subtract 8 from both sides and you get -13=b.