`4^{10} . 2^{30}`
`= (2^{2})^{10} . 2^{30}`
`= 2^{20} . 2^{30}`
`= 2^{50}`
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`9^{25} . 27^{4} . 81^{3}`
`= (3^{2})^{25} . (3^{3})^{4} . (3^{4})^{3}`
`= 3^{50} . 3^{12} . 3^{12}`
`= 3^{74}`
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`25^{50} . 125^{5}`
`= (5^{2})^{50} . (5^{3})^{5}`
`= 5^{100} . 5^{15}`
`= 5^{115}`
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`64^{3} . 4^{8} . 16^{4}`
`= (2^{6})^{3} . (2^{2})^{8} . (2^{4})^{4}`
`= 2^{18} . 2^{16} . 2^{16}`
`= 2^{50}`