PLEASE HELP ME
Factor the trionomial below. X2-4x-12

Tim's phone service charges $23.06 plus an additional $0.22 for each text message sent per month. if tim's phone bill was $28.56, which equation could be used to find how many text messages, x, tim sent last month?

Asystem of equations has 1 solution.if 4x-y=5 is one of the equations , which could be the other equation ?

Ibeg you to me 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?