Y^2 -40y +c find the value of c that completes the square

Use the diagonals to determine whether a parallelogram with vertices u(2,−2), v(9,−2), w(9,−6), and x(2,−6) is a rectangle, rhombus, or square. give all the names that apply.

What is the solution of sqrt x+2-15=-3

How do you find the area of a triangle