多项式的正, 负区间

$f(x)=x(4x+9)(x-2)(2x-9)(x+5)$f, left parenthesis, x, right parenthesis, equals, x, left parenthesis, 4, x, plus, 9, right parenthesis, left parenthesis, x, minus, 2, right parenthesis, left parenthesis, 2, x, minus, 9, right parenthesis, left parenthesis, x, plus, 5, right parenthesis这个方程的零出现在$x=-5$x, equals, minus, 5，$x=-\dfrac{9}{4}$x, equals, minus, start fraction, 9, divided by, 4, end fraction，$x=0$x, equals, 0， $x=2$x, equals, 2，以及$x=\dfrac{9}{2}$x, equals, start fraction, 9, divided by, 2, end fraction。

$f$f在$0<x< 2\$0, is less than, x, is less than, 2, space这段间隔中的输出是正或负?