I really need help with solving perimeter problems. I have every messenger, and if you have 1 and can help me with problems like:

-The perimeter of a rectangle is 48 centimeters. If the length of the rectangle is 16 centimeters, find its width.

Or

-The length of a side of an equilateral triangle is represented by X + 5. Represent the perimeter of the triangle.

If you can help me with problems similar to those please leave feedback, and the messenger you have with your screen name. I need help quickly because schools tomorrow Thank you. Im sorry if i posted this again, but im really despirate for help and im doing horrible in 9th grade math