Can someone pls help :)

Solve the system of equations. y= 2x y= x^2 - 15

Find the height of a square pyramid that has the volume of 32 ft.³ and a base lengthof 4 feet

Players on the school soccer team are selling candles to raise money for an upcoming trip. each player has 24 candles to sell. if a player sells 4 candles a profit of$30 is made. if he sells 12 candles a profit of $70 is made. determine an equation to model his situation?