You found your area wrong as soon as you gt 192 you multiply by 0.50 getting 96 then you divide by 20 to get 4.8 centimeters
193/990 Would be the answer. If you want the steps to find it, just ask.
3x^2-18+5=47
3x^2 = 60
x^2 = 20
x = 4.472 , x = - 4.472
As determined by the graph, f(-9) = 9
