This circle is centered at the origin, and the length of it’s radius is 4. What is the equation of the circle?

Which of the following is the result of expanding

Koji is installing a rectangular window in an office building. the window is 823 feet wide and 534 feet high. the formula for the area of a rectangle is a=bh. what is the area of the window? enter your answer as a mixed number in simplest form in the box. $$ ft2

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827