\(\frac{7\cdot12^8\cdot5^4-6^9\cdot20^4}{6^{10}\cdot10^5-7\cdot3^9\cdot80^4}\)
tính nhanh
\(\frac{1\cdot5\cdot6+2\cdot10\cdot12+4\cdot20\cdot24+9\cdot45\cdot54}{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot2\cdot20+9\cdot27\cdot45}\)
\(\frac{1.5.6+2.10.12+4.20.24+9.45.54}{1.3.5+2.6.10+4.12.20+9.27.45}\)
\(=\frac{1.5.3.2+2.10.6.2+4.20.12.2+9.45.27.2}{1.3.5+2.6.10+4.12.20+9.27.45}\)
\(=\frac{2\left(1.3.5+2.6.10+4.12.20+9.27.45\right)}{1.3.5+2.6.10+4.12.20+9.27.45}\)
\(=2\)
A=\(A=\frac{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20+7\cdot25\cdot35}{1\cdot5\cdot7+2\cdot10\cdot19+4\cdot20\cdot28+7\cdot35\cdot49}\)
* là dấu nhân
Giá trị của biểu thức \(C=\frac{1\cdot5\cdot6+2\cdot10\cdot12+4\cdot20\cdot24+...+9\cdot45\cdot54}{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20+...+9\cdot27\cdot45}\) là \(C=\)
\(C=\frac{1.5.3.2+2.10.6.2+4.20.12.2+...+9.45.27.2}{1.3.5+2.6.10+4.12.20+...+9.27.45}\)
\(C=\frac{2\left(1.5.3+2.10.6+4.20.12+...+9.45.27\right)}{1.3.5+2.6.10+4.12.20+...+9.27.45}\) = 2
Tính nhanh
A=\(\frac{1\cdot5\cdot6+2\cdot10\cdot12+3\cdot15\cdot18+4\cdot20\cdot24+5\cdot25\cdot30}{1\cdot3\cdot5+2\cdot6\cdot10+3\cdot9\cdot15+4\cdot12\cdot20+5\cdot15\cdot25}\)
A=1.5.(3.2)+2.10.(6.2)+3.15.(9.2)+4.20.(12.2)+5.25.(15.2)
1.3.5+2.6.10+3.9.15+4.12.20+5.15.25
A=1.5.3+2.10.6+3.15.9+4.20.12+5.25.15(2.2.2.2.2)
1.3.5+2.6.10+3.9.15+4.12.20+5.15.25
A=2.2.2.2.2
A=32
\(\frac{1\cdot3\cdot5\cdot2+2\cdot10\cdot6\cdot2+3\cdot15\cdot9\cdot2+4\cdot20\cdot12\cdot2+5\cdot25\cdot15\cdot2}{1\cdot3\cdot5+2\cdot10\cdot6+3\cdot15\cdot9+4\cdot20\cdot12+5\cdot25\cdot15 }\)
\(2\cdot2\cdot2\cdot2\cdot2=2^5\)
\(=32\)
làm bừa thui,ai trên 11 điểm tích mình mình tích lại
Số số hạng là :
Có số cặp là :
50 : 2 = 25 ( cặp )
Mỗi cặp có giá trị là :
99 - 97 = 2
Tổng dãy trên là :
25 x 2 = 50
Đáp số : 50
\(\dfrac{1\cdot2\cdot3+2\cdot4+6+4\cdot8\cdot12}{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20}\)
\(\dfrac{1\cdot2\cdot3+2\cdot4\cdot6+4\cdot8\cdot12}{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20}\\ =\dfrac{1\cdot2\cdot3+2\cdot1\cdot2\cdot2\cdot2\cdot3+4\cdot1\cdot4\cdot2\cdot4\cdot3}{1\cdot3\cdot5+2\cdot1\cdot2\cdot3\cdot2\cdot5+4\cdot1\cdot4\cdot3\cdot4\cdot5}\\ =\dfrac{1\cdot2\cdot3\cdot\left(1+2^3+4^3\right)}{1\cdot3\cdot5\cdot\left(1+2^3+4^3\right)}\\ =\dfrac{1\cdot2\cdot3}{1\cdot3\cdot5}\\ =\dfrac{6}{15}\)
Bạn ghi đề sai rồi, mình sửa lại đề ở phần (*) rồi nhé! ![]()
Ta có: \(\dfrac{1.2.3+2.4.6+4.8.12}{1.3.5+2.6.10+4.12.20}\) (*)
= \(\dfrac{1.2.3\left(1+2^3+4^3\right)}{1.3.5\left(1+2^3+4^3\right)}\) = \(\dfrac{1.2.3}{1.3.5}\) = \(\dfrac{2}{5}\)
so sánh\(\frac{1\cdot3\cdot5+2\cdot6+4\cdot12\cdot20+7\cdot21\cdot35}{1\cdot5\cdot7+2\cdot10\cdot14+4\cdot20\cdot28+7\cdot35\cdot49}\)với \(\frac{303}{708}\)
\(=\frac{219}{520}=\frac{155052}{368160}\)
\(=\frac{303}{708}=\frac{157560}{368160}\)
\(\frac{155052}{368160}< \frac{157560}{368160}\)
VẬY \(\frac{303}{708}\)LỚN HƠN
\(A=\frac{1.5\cdot6+2\cdot10\cdot12+3\cdot15\cdot18+4\cdot20\cdot24+5\cdot25\cdot30}{1\cdot3\cdot5+2\cdot6\cdot10+3\cdot9\cdot15+4\cdot12\cdot20+5\cdot15\cdot25}\)
=\(\frac{30\left(1+8+27+64+125\right)}{5\left(3+24+81+64+375\right)}\)
= \(\frac{30.225}{5.574}\)
=\(\frac{6750}{2870}\)
=\(\frac{675}{287}\)
K mình với!!!!
1)So sánh
\(\dfrac{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20+7\cdot21\cdot35}{1\cdot5\cdot7+2\cdot10\cdot14+4\cdot20\cdot28+7\cdot35\cdot45}\)với\(\dfrac{303}{708}\)
\(\dfrac{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20+7\cdot21\cdot35}{1\cdot5\cdot7+2\cdot10\cdot14+4\cdot20\cdot28+7\cdot35\cdot45}\)
=\(\dfrac{3+6+12+21\cdot35}{14+28+7\cdot45}\)
=\(\dfrac{450}{119}\)
Vì \(\dfrac{450}{119}>1\) mà \(1>\dfrac{303}{708}\)
\(\Rightarrow\)\(\dfrac{450}{119}>\dfrac{303}{708}\)
thực hiện phếp tính
\(\frac{\frac{2}{3}+\frac{2}{7}-\frac{1}{4}}{-1-\frac{3}{7}+\frac{3}{28}}\)
\(\frac{1\cdot2+2\cdot4+3\cdot6+4\cdot8+5\cdot10}{3\cdot4+6\cdot3+9\cdot12+12\cdot16+15\cdot20}\)
cảm ơn kết quả thì mik b òi nhưng mik cần cách làm