Please help, algebra is annoying

Christina can paint 420 square feet in 105 minutes. which unit rate describes the scenario?

Using elimination, what is -4x+2y=-12 4x+8y=-24

Which statements describe the solutions to the inequality x< -20 check all that apply. there are infinite solutions. each solution is negative. each solution is positive. the solutions are both positive and negative. the solutions contain only integer values. the solutions contain rational number values.