Please help me solve this

Simplify the expression. -2/5(10+15m-20n)

Television sizes are based on the length of the diagonal of the television's rectangular screen. so, for example, a 70-inch television is a television having a diagonal screen length of 70 inches. if a 70 inch television's diagonal forms a 29°angle with the base of the screen, what is the vertical height (1) of the screen to the nearest inch? 70 inhin

Which of the following would be a good name for the function that takes the weight of a box and returns the energy needed to lift it?