If current rates of deforestation and fossil fuel consumption continue, then the amount of atmospheric carbon dioxide in parts per million (ppm) will be given by $f(x)=375 e^{00609 x},$ where $x=0$ corresponds to 2000
(a) What is the amount of carbon dioxide in $2003 ?$ In $2022 ?$
(b) In what year will the amount of carbon dioxide reach $500 \mathrm{ppm} ?$