Here is a pic of the graph
5 and 20 because if the perimeter is 50 the width is 5 and 5 x 4 is 20
Definitely zero (0)............
Well..

get both, check their difference, that's how much more tax you'd be paying from 7.5% to 8% on $10
Method 1.
Use the formula of a distance between two points:

We have

substitute

Answer: 10
Method 2
Look at the picture.
Use the Pythagorean theorem:

Answer: 10