\(\frac{45^{10}20^{10}}{75^{15}}\)=\(\frac{1125^{10}}{75^5.75^{10}}\)=\(\frac{1125^{10}}{75}\)=\(\frac{1}{75^5}\)=\(\frac{15^{10}}{75^5}\)=\(\frac{15^5.15^5}{75^5}\)=\(\frac{15^5}{75}\).\(15^5\)=\(\frac{1^5}{3}\).\(15^5\)=\(\frac{1}{3}.15^5\)=\(^{5^5}\)=3125