giúp mình vói ạ 25^13.7^29 – 5^25. 49^15 : 125^9. 7^29+5^25.(-7)^30

Giải đáp: $-\dfrac{1}{16}$

 

$\dfrac{{{25}^{13}}{{.7}^{29}}-{{5}^{25}}{{.49}^{15}}}{{{125}^{9}}{{.7}^{29}}+{{5}^{25}}.{{\left( -7 \right)}^{30}}}$

$=\dfrac{{{\left( {{5}^{2}} \right)}^{13}}{{.7}^{29}}-{{5}^{25}}.{{\left( {{7}^{2}} \right)}^{15}}}{{{\left( {{5}^{3}} \right)}^{9}}{{.7}^{29}}+{{5}^{25}}{{.7}^{30}}}$

$=\dfrac{{{5}^{26}}{{.7}^{29}}-{{5}^{25}}{{.7}^{30}}}{{{5}^{27}}{{.7}^{29}}+{{5}^{25}}{{.7}^{30}}}$

$=\dfrac{{{5}^{25}}{{.7}^{29}}\left( 5-7 \right)}{{{5}^{25}}{{.7}^{29}}\left( {{5}^{2}}+7 \right)}$

$=\dfrac{-2}{32}$

$=-\dfrac{1}{16}$