Tính:
\(A=\frac{1.5.6+2.10.12+4.20.24+.....+9.45.54}{1.3.5+2.6.10+4.12.20+.....+9.27.45}\)
tính nhanh A=1.5.6+2.10.12+4.20.24+9.45.54/ 1.3.5+2.6.10+4.12.20+9.27.45
Tính nhanh
a) 1.5.6+2.10.12+4.20.24+9.45.54
1.3.5+2.6.10+4.12.20+9.27.45
\(\frac{1\cdot5\cdot6+2\cdot10\cdot12+4\cdot20\cdot24+9\cdot45\cdot54}{1\cdot3\cdot5+2\cdot6\cdot10+4\cdot12\cdot20+9\cdot27\cdot45}=\frac{1\cdot5\cdot6\cdot\left(1+2+4+9\right)}{1\cdot3\cdot5\cdot\left(1+2+4+9\right)}=2\)
\(A=\frac{1.5.6+2.10.12+4.20.24+...+9.45.54}{1.3.5+2.6.10+4.12.20+...+9.27.45}\)
A=\(\frac{1.5.6+8\left(1.5.6\right)+64\left(1.5.6\right)+...+729\left(1.5.6\right)}{1.3.5+8\left(1.3.5\right)+64\left(1.3.5\right)+...+729\left(1.3.5\right)}\)
=\(\frac{\left(1.5.6\right)\left(1+8+64+...+729\right)}{\left(1.3.5\right)\left(1+8+64+...+729\right)}\)
=\(\frac{1.5.6}{1.3.5}\)
=2
Tính nhanh \(\frac{1.5.6+2.10.12+4.20.24+9.45.54}{1.3.5+2.6.10+4.12.20+9.27.45}\)
\(A=\frac{1.5.6+2^3.1.5.6+4^3.1.5.6+9^3.1.5.6}{1.3.5+2^3.1.3.5+4^3.1.3.5+9^3.1.3.5}=\frac{1.5.6.\left(1+2^3+4^3+9^3\right)}{1.3.5.\left(1+2^3+4^3+9^3\right)}=2\)
Tính nhanh:
\(\frac{1.5.6+2.10.12+4.20.24+9.45.54}{1.3.5+2.6.10+4.12.20+9.27.45}\)
\(\frac{1.5.6+2.10.12+4.20.24+9.45.54}{1.3.5+2.6.10+4.12.20+9.27.45}\)=\(\frac{1.5.6+\left(1.5.6\right)2+\left(1.5.6\right)4+\left(1.5.6\right)9}{1.3.5+\left(1.3.5\right)2+\left(1.3.5\right)4+\left(1.3.5\right)9}\)
=\(\frac{\left(1.5.6\right)\left(1+2+4+9\right)}{\left(1.3.5\right)+\left(1+2+4+9\right)}=\frac{1.5.6}{1.3.5}=\frac{6}{3}=2\)
\(\frac{1.5.6+2.10.12+4.20.24+9.45.54}{1.3.5+2.6.10+4.12.20+9.27.45}=\frac{1.5.6+\left(1.5.6\right)2+\left(1.5.6\right)4+\left(1.5.6\right)9}{1.3.5+\left(1.3.5\right)2+\left(1.3.5\right)4+\left(1.3.5\right)9}=\)
\(\frac{\left(1.5.6\right)\left(1+2+4+9\right)}{\left(1.3.5\right)\left(1+2+4+9\right)}=\frac{1.5.6}{1.3.5}=\frac{6}{3}=2\)
\(\frac{1.5.6+2.10.12+4.20.24+9.45.54}{1.3.5+2.6.10+4.12.20+9.27.45}\)
\(=\frac{1.5.6+\left(1.5.6\right)2+\left(1.5.6\right)4+\left(1.5.6\right)9}{1.3.5+\left(1.3.5\right)2+\left(1.3.5\right)4+\left(1.3.5\right)9}\)
\(=\frac{\left(1.5.6\right)\left(1+2+4+9\right)}{\left(1.3.5\right)\left(1+2+4+9\right)}\)
\(=\frac{1.5.6}{1.3.5}=\frac{6}{3}=2\)
tính nhanh \(\frac{1.5.6+2.10.12+4.20.24+9.45.54}{1.3.5+2.6.10+4.12.20+9.27.45}\)
Giá tri của biểu thức 1.5.6+2.10.12+4.20.24+..+9.45.54:1.3.5+2.6.10+4.12.20+...+9.27.45=
Ta có: C = (1.5.6+2.10.12+4.20.24+..+9.45.54):(1.3.5+2.6.10+4.12.20+...+9.27.45)
= (1.3.5.2+2.6.10.2+4.12.20.2+...+9.27.45.2):(1.3.5+2.6.10+4.12.20+...+9.27.45)
= (2.(1.3.5+2.6.10+4.12.20+...+9.27.45)):(1.3.5+2.6.10+4.12.20+...+9.27.45)
=2
Bằng 2 bạn nhé
k cho mk dc k.đi..................................................
\(C=\frac{1.5.6+2.10.12+4.20.24+...+9.45.54}{1.3.5+2.6.10+4.12.20+...+9.27.45}\)
tính nhanh
1.5.6+2.10.12+4.20.24+9.45.54/1.3.5+2.6.10+4.12.20+9.27.45