Question

\(\text{Bài 1 : Tính}\)

\(A=\frac{2^2\cdot10+2^3\cdot6}{2^2\cdot15-2^4}\)

\(B=\frac{2^9\cdot15^{17}\cdot75^3}{18^8\cdot5^{24}\cdot9^2}\)

\(C=\frac{7^{28}+7^{24}+...+7^4+7^0}{7^{30}+7^{28}+...+7^2+7^0}\)

Answer 1

Bài làm

\(A=\frac{2^2.10+2^3.6}{2^2.15-2^4}\)

\(A=\frac{2^2.10+2.2^2.6}{2^2.15-2^2.2^2.1}\)

\(A=\frac{2^2.\left(10+6\right).2}{2^2.\left(15-1\right).2^2}\)

\(A=\frac{2^2.16.2}{2^2.14.2^2}\)

\(A=\frac{16}{14.2}\)

\(A=\frac{8}{7.2}\)

\(A=\frac{8}{14}\)

\(A=\frac{4}{7}\)

Vậy \(A=\frac{4}{7}\)

Answer 2

\(B=\frac{2^9.15^{17}.75^3}{18^8.5^{24}.9^2}\)

\(B=\frac{2^9.\left(3.5\right)^{17}.\left(3.5^2\right)^3}{\left(2.3^2\right)^8.5^{24}.\left(3^2\right)^2}\)

\(B=\frac{2^9.3^{17}.5^{17}.3^3.5^6}{2.3^{19}.5^{24}.3^4}\)

\(B=\frac{2^8.1.1.1.5}{1.3^2.1.3}\)

\(B=\frac{2^8.5}{3^3}\)

\(B=\frac{1280}{27}\)