\(\frac{50^{15}.13^{18}}{25^7.26^{15}.5^{16}}=\frac{\left(5.5.2\right)^{15}.13^{18}}{\left(5.5\right)^7.\left(13.2\right)^{15}.5^{16}}=\frac{5^{15}.5^{15}.2^{15}.13^{18}}{5^7.5^7.13^{15}.2^{15}.5^{16}}=\frac{5^{30}.2^{15}.13^{18}}{5^{30}.13^{15}.2^{15}}=13^3=2197\)