17 The function f(x) is graphed below. f(x) -X The domain of this function is (1) all positive real numbers (2) all positive integers (3) x 0 (4) x-1 18 Which pair of equations would have (-1,2) as a solution? (1) y=x+3 and y = 2* (2) y=x-1 and y = 2x (3) y = x-3x-2 and y = 4x + 6 3