Annual profit in thousands of dollars is given by the function, P(x) = -.1x2 + 50x - 300, where x is the number of items sold, x ≥ 0.

describe the meaning of the number -.1 in the formula, in terms of its meaning in relation to the profit.
describe the meaning of the number -300 in the formula, in terms of its meaning in relation to the profit.
find the profit for 5 different values of x