Why is this function linear?

1.) 2x + y = 3 2.) x - 2y = -1 if equation 1 is multiplied by 2 and then the equations are added, the result is a.3x = 2 b.3x = 5 c.5x = 5

Which of the following represents the range of the graph of f(x) below

Factor the polynomial by its greatest common monomial factor.