Simplify: 5x+9y-7x+2-5y-7x+2-3x

please help

You give a $4 tip for a meal that cost $22. approximately what percent of the bill was your tip?

The boiling point of water at an elevation of 0 feet is 212 degrees fahrenheit (°f). for every 1,000 feet of increase in elevation, the boiling point of water decreases by about 2°f. which of the following represents this relationship if b is the boiling point of water at an elevation of e thousand feet? a) e = 2b - 212 b) b = 2e - 212 c) e = -2b + 212 d) b = -2e + 212

V=x^4-y^4 pick three expressions that can represent the three dimensions of the prism (each in meters)