\(=\frac{7^5.2^{18}}{7^2.2^8}=7^3.2^{10}\)

\(\frac{-7^5.4^9}{-49.2^8}\)

\(=\frac{-7^5.\left(2^2\right)^9}{-7^2.2^8}\)

\(=\frac{-7^5.2^{18}}{-7^2.2^8}\)

\(=7^3.2^{10}\)

\(\frac{-7^5.4^9}{-49.2^8}\)=\(\frac{-7^5.2^{18}}{-7^2.2^8}\)=\(7^3.2^{10}\)=343.1024=351232

Cả tử số và mẫu số đều là số có hai chữ số

+) Trên tử: chữ số hàng chục nhỏ hơn chữ số hàng đơn vị

+) Dưới mẫu: chữ số hàng chục lớn hơn chữ số hàng đơn vị

a) Ta có: \(\frac{2\cdot\left(-13\right)\cdot9\cdot10}{\left(-3\right)\cdot4\cdot\left(-5\right)\cdot26}=\)\(\frac{2\cdot\left(-1\right)\cdot13\cdot3\cdot3\cdot2\cdot5}{3\cdot\left(-1\right)2\cdot2\cdot\left(-1\right)\cdot5\cdot2\cdot13}\)=\(-3.\)

b)Ta có: \(\frac{15\cdot8+15\cdot4}{12\cdot3}=\frac{15\left(8+4\right)}{12\cdot3}\)=\(\frac{15\cdot12}{12\cdot3}=\frac{15}{3}=5\)

\(\frac{15^5.2^6.3^3}{5^6.6^8}=\frac{5^5.3^5.2^6.3^3}{5^6.2^8.3^8}=\frac{5^5.3^8.2^6}{5^6.2^8.3^8}=\frac{1}{5.2^2}=\frac{1}{5.4}=\frac{1}{20}\)

= 1/20 nha bn

\(\frac{5^6.8-5^7}{5^8-7.5^6}\)

\(=\frac{5^6.8-5^6.5}{5^6.5^2-7.5^6}\)

\(=\frac{5^6\left(8-5\right)}{5^6\left(25-7\right)}\)

\(=\frac{5^6.3}{5^6.18}=\frac{3}{18}=\frac{1}{6}\)

làm giúp mình nha

\(\frac{5^6.8-5^7}{5^8-7.5^6}=\frac{5^6.\left(1.8-5\right)}{5^6.\left(5^2-7\right)}=\frac{5^6.3}{5^6.18}=\frac{5^6.3}{5^6.3.6}=\frac{1}{6}\)

\(=\frac{1.3}{2.2}.\frac{2.4}{3.3}\frac{3.5}{4.4}.....\frac{29.31}{30.30}=\frac{\left(1.2.3....29\right)\left(3.4.5....31\right)}{\left(2.3.4....30\right)\left(2.3.4....30\right)}=\frac{31}{30.2}=\frac{31}{60}\)

a, ta có \(\frac{2.\left(-13\right).9.10}{\left(-3\right).4.\left(-5\right).26}\)=\(\frac{2.\left(-13\right).\left(-3\right).\left(-3\right).2.\left(-5\right)}{\left(-3\right).2.2.\left(-5\right).\left(-2\right).\left(-13\right)}\)

rút gọn đi còn: \(\frac{-3}{-2}\)=\(\frac{3}{2}\)

15×8+15×4/12×3

= 15×(8+4)/12×3

=15×12/12×3

=15/3

=5

\(\frac{2+x}{2-x}\div\frac{4x^2}{4-4x+x^2}\times\left(\frac{2}{2-x}-\frac{8}{8+x^3}\times\frac{4-2x+x^2}{2-x}\right)\)

\(=\frac{2+x}{2-x}\times\frac{4-4x+x^2}{4x^2}\times\left(\frac{2}{2-x}-\frac{8}{\left(2+x\right)\left(4-2x+x^2\right)}\times\frac{4-2x+x^2}{2-x}\right)\)

\(=\frac{2+x}{2-x}\times\frac{\left(2-x\right)^2}{4x^2}\times\left(\frac{2\left(2+x\right)}{\left(2+x\right)\left(2+x\right)}-\frac{8}{\left(2+x\right)\left(2-x\right)}\right)\)

\(=\frac{\left(2+x\right)\left(2-x\right)}{4x^2}\times\frac{4+2x-8}{\left(2+x\right)\left(2-x\right)}\)

\(=\frac{2\left(2+x-4\right)}{4x^2}\)

\(=\frac{x-2}{2x^2}\)