\(B=\frac{5^{13}.7^{18}+5^{14}.7^{17}}{5^{13}.7^{17}}=\frac{5^{13}.7^{17}.\left(7+5\right)}{5^{13}.7^{17}}=12\)
Các câu hỏi tương tự
Chứng minh rằng :
a) \(7^{11}\cdot7^{13}\cdot7^{17}⋮49\)
b) \(4+3+3^2+3^3+...+3^{200}⋮13;2\)
c) \(1+2^2+2^4+...+2^{98}+2^{100}⋮21\)
d) \(5+5^2+5^3+...+5^{2004}⋮6;31\)
e) \(2+2^2+2^3+...+2^{120}⋮7;31;5\)
\(\frac{4}{3\cdot7}+\frac{5}{7\cdot12}+\frac{1}{12\cdot13}+\frac{7}{13\cdot20}+\frac{3}{20\cdot23}\)
\(\frac{4}{3\cdot7}+\frac{5}{7\cdot12}+\frac{1}{12\cdot13}+\frac{7}{13\cdot20}+\frac{8}{20\cdot28}\)
\(\frac{ }{\frac{4}{3\cdot7}+\frac{5}{7\cdot12}+\frac{1}{12\cdot13}+\frac{7}{13\cdot20}+\frac{3}{20\cdot23}}\)
Hãy tính các tổng sau:
a)dfrac{1}{1cdot3}+dfrac{1}{3cdot5}+dfrac{1}{5cdot7}+dfrac{1}{7cdot9}+dfrac{1}{9cdot11}
b)dfrac{1}{4cdot7}+dfrac{1}{7cdot10}+dfrac{1}{10cdot13}+dfrac{1}{13cdot16}
c)dfrac{1}{2cdot7}+dfrac{1}{7cdot12}+dfrac{1}{12cdot17}+...
Đọc tiếp
Hãy tính các tổng sau:
a)\(\dfrac{1}{1\cdot3}\)+\(\dfrac{1}{3\cdot5}\)+\(\dfrac{1}{5\cdot7}\)+\(\dfrac{1}{7\cdot9}\)+\(\dfrac{1}{9\cdot11}\)=
b)\(\dfrac{1}{4\cdot7}\)+\(\dfrac{1}{7\cdot10}\)+\(\dfrac{1}{10\cdot13}\)+\(\dfrac{1}{13\cdot16}\)=
c)\(\dfrac{1}{2\cdot7}\)+\(\dfrac{1}{7\cdot12}\)+\(\dfrac{1}{12\cdot17}\)+...=
B=\(\frac{5}{1\cdot4}\)+\(\frac{5}{4\cdot7}\)+\(\frac{5}{7\cdot10}\)+\(\frac{5}{10\cdot13}\)+\(\frac{5}{13\cdot16}\)
\(\frac{\left(2^3\cdot5\cdot7\right)\cdot\left(5^2\cdot7^3\right)}{\left(2\cdot5\cdot7^2\right)^2}\) = ?
Tính giá trị biểu thức
\(E=\frac{\left(2^3\cdot5\cdot7\right)\cdot\left(5^2\cdot7^3\right)}{\left(2\cdot5\cdot7^2\right)^2}\)
rút gọn
\(\frac{2^{10}\cdot3^{10}-2^{10}\cdot3^9}{2^9\cdot3^{10}}\) \(\frac{5^{11}\cdot7^{12}+5^{11}\cdot7^{11}}{5^{12}\cdot7^{12}+9\cdot5^{11}\cdot7^{11}}\) \(\frac{1998\cdot1990+3978}{1992\cdot1991-3984}\)