a) $3^{2}$.$5^{2}$+$\frac{15.7}{22.6}$+$\frac{18}{11}$
= 9.25+$\frac{105}{132}$+$\frac{18}{11}$
= 9.25+$\frac{35}{44}$+$\frac{18}{11}$
= 225+$\frac{35}{44}$+$\frac{18}{11}$
= $\frac{225}{1}$+$\frac{35}{44}$+$\frac{18}{11}$
= $\frac{9900}{44}$+$\frac{35}{44}$+$\frac{72}{44}$
= $\frac{10007}{44}$
b) (-4).35+(-5).$\frac{11}{7}$.(-25)+2.(-15)
= -140+$\frac{-55}{7}$.(-55)
= $\frac{-140}{1}$+$\frac{-385}{1}$.$\frac{-55}{1}$
= $\frac{-140}{1}$+$\frac{21175}{1}$
= 21035
