Hello, Sandi,
The line y = -9x - 1 in in the standard format of y = mx + b, where m is the slope. A perpendicular line will have a slope that is the inverse negative of this slope. So -9 becomes +(1/9) in the new line.
y = (1/9)x + b will be perpendicular. But we need to find b since we are told the line goes through point (0,0). [Is (0,0) correct?]. We can input that data point into the equation to find b:
y = (1/9)x + b
0 = (1/9)*0 + b
b = 0
So the equation becomes simply y = (1/9)x (the blue line)
Bob
