Răspuns:
Salutare!
(5⁹×7⁸)²¹=
[tex](5 \times {5} ^{8} \times {7}^{8)} {21} =( 5 \times 35 ^{8} ) {?}^{21} = {5}^{21} \times 35 {}^{168} [/tex]
