Find the exact value of sin(x+y) if sin(x)=3/5 and cos(y)=-5/13, if 0 help please!!

Cindy uses 1-inch cubes to find the volume of a jewelry box shaped like a rectangular prism. she uses 780 cubes to completely fill the jewelry box with no gaps or overlaps. if the jewelry box is 13 inches long and 5 inches wide, how tall is cindy’s jewelry box?

For the function, f(x) = -5x 2, find f(-4).

Segment xz is bisected by point y. if xy = 12x, and the measure of xz = 18x – 6, solve for x