tử số : 2.4 + 4.8 + 8.12 + 12.16 + 16.20
= 2.(1.2+2.4+4.6+6.8+8.10)
ta được 2. A=( 1.2+2.4+4.6+6.8+8.10) / ( 1.2+2.4+4.6+6.8+8.10)
=> A=2
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Các câu hỏi tương tự
Rút gọn \(A=\frac{2\cdot4+4\cdot8+8\cdot12+12\cdot16+16\cdot20}{1\cdot2+2\cdot4+4\cdot6+6\cdot8+8\cdot10}\) ta được A=
thực hiện phếp tính
\(\frac{\frac{2}{3}+\frac{2}{7}-\frac{1}{4}}{-1-\frac{3}{7}+\frac{3}{28}}\)
\(\frac{1\cdot2+2\cdot4+3\cdot6+4\cdot8+5\cdot10}{3\cdot4+6\cdot3+9\cdot12+12\cdot16+15\cdot20}\)
\(20\%x+\frac{2}{5}x=x-4\)
\(\frac{\frac{2}{3}+\frac{2}{7}\cdot\frac{1}{14}}{-1-\frac{3}{7}+\frac{3}{28}}\)
\(\frac{1\cdot2+2\cdot4+3\cdot6+4\cdot8+5\cdot10}{3\cdot4+6\cdot8+9\cdot12+12\cdot16+15\cdot20}\)
giải hội mik mới cách làm lun nha
Rút gọn rồi so sánh
A=\(\dfrac{8056}{2012\cdot16-1982}\)
B=\(\dfrac{1\cdot2\cdot6+2\cdot4\cdot12+4\cdot8\cdot24+7\cdot14\cdot42}{1\cdot6\cdot9+2\cdot12\cdot18+4\cdot24\cdot36+7\cdot42\cdot63}\)
So sánh A và B
\(\frac{2\cdot4\cdot10+4\cdot6\cdot8+14\cdot16\cdot20}{3\cdot6\cdot15+6\cdot9\cdot12+21\cdot24\cdot30}\)
CÁC BN LÀM HỘ MK NHÉ
\(a=\frac{2\cdot9\cdot8+3\cdot12\cdot10+4\cdot15\cdot12+...+98\cdot297\cdot200}{23\cdot4+3\cdot4\cdot5+4\cdot5\cdot6+...+98\cdot99\cdot100}\)
Tính a2
Giúp mình với!
CHO \(a=\frac{2\cdot9\cdot8+3\cdot12\cdot10+4\cdot15\cdot12+...+98\cdot297\cdot200}{23\cdot4+3\cdot4\cdot5+4\cdot5\cdot6+...+98\cdot99\cdot100}\)
Tính a2
Rút gọn:
a,\(A=\frac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^9\cdot6^{19}-7\cdot2^{29}\cdot27^6}\)
b,\(B=\left(1+\frac{1}{1\cdot3}\right)\left(1+\frac{1}{2\cdot4}\right)\left(1+\frac{1}{3\cdot5}\right)...\left(1+\frac{1}{2014\cdot2016}\right)\)
A=\(\frac{15\cdot3^{11}+4.27^4}{9^7}\)
B=\(\frac{2^{19}\cdot2^{73}+15\cdot4^9\cdot9^4}{6^9\cdot2^{10}+12^{10}}\)
C=\(\frac{5\cdot12^3\cdot4^{11}-16^8}{\left(3\cdot2^{17}\right)^2}\)
D=\(\frac{4^7\cdot2^8}{3\cdot2^{15}\cdot16^2-5\cdot2^2\cdot\left(2^{10}\right)^2}\)