Can somebody tell me if this is factorable? i've been trying this with a friend and we can't come up with any numbers. x^2 + 9x - 4

The input to the function is x and the output is y. write the function such that x can be a vector (use element-by-element operations). a) use the function to calculate y(-1.5) and y(5). b) use the function to make a plot of the function y(x) for -2 ≤ x ≤ 6.