w is the width and it is the independent variable. You can pick any positive whole number you want (within reason of course; you can't go to infinity or go beyond some set boundary). Whatever you picked for w, the expression 2w-5 will be dependent on it. So the length is dependent on the width.
For instance, if the width is w = 10 feet, then 2w-5 = 2*10-5 = 20-5 = 15 feet is the length. The choice of 10 feet for the width directly affects the length being 15 feet.
Try this option:
1. according to the line on the graph x≥0 and x<9.
2. in answers a;b;c;d;e x<0, only in answer f. √x<3, x>0. It means, that answer 'f' is correct.
answer: f.
A = pi r^2
A = 5^2 pi
A = 25 Pi
so semi-circle = 25 pi / 2
answer is a) 25 pi / 2 m^2