computing areas and perimeters of simple figures and other stuff

i dont understand these problemss.....please help me on them i got a summer packet and i dont understand almost none of the problemsss(Crying)anyway here are the problems

if the area of a circle is 64pi, then what is the circumfrence?

if the minute hand of a clock moves 45 degrees, how many minutes of time have passed?

a triangle of height 5 and base 4 has an area exactly 1/3 that of a rectangle with height 5 . what is the width of the rectangle?

here are some other problems i dont understand..

it says : determine a table of values for the domain of integers within

-6< x< 6

then it says :5x+3y=26

and it has another problem

3x-3y=27