Adding two functions results in h(x) = –x + 9, while multiplying the same functions results in j(x) = –9x. which statements describe f(x) and g(x), the original functions? select two options. both functions must be quadratic. both functions must have a constant rate of change. both functions must have a y-intercept of 0. the rate of change of either f(x) or g(x) must be 0. the y-intercepts of f(x) and g(x) must be opposites.