Range represents the set of values which the given function \[-5x^{2}+9\]
can assume. The function is quadratic and the square terms can only assume positive values. But the sign of the square term is negative so the overall square term with sign can only assume negative values. Maximum negative value possible is - infinity. Square term has the highest value of 0. On this case the value of the function becomes 9. So the range of the function is (−∞, −9].
