Tính nhanh :
4 x 7/5731 x 1/3759 - 4/3759 x 1/2/3759 + 1/3759.5731
Tính nhanh
E=\(4\dfrac{7}{5741}.\dfrac{1}{3759}-\dfrac{4}{3759}.1\dfrac{2}{5741}+\dfrac{1}{3759}+\dfrac{1}{3759.5741}\)
Đặt 3759=a; 5741=b
Theo đề, ta có: \(E=4\dfrac{7}{b}\cdot\dfrac{1}{a}-\dfrac{4}{a}\cdot\left(1+\dfrac{2}{b}\right)+\dfrac{1}{a}+\dfrac{1}{ab}\)
\(=\dfrac{4b+7}{b}\cdot\dfrac{1}{a}-\dfrac{4}{a}\cdot\dfrac{b+2}{b}+\dfrac{b+1}{ab}\)
\(=\dfrac{4b+7-4b-8+b+1}{ab}=\dfrac{b}{ab}=\dfrac{1}{a}=\dfrac{1}{3759}\)
Tính
1/ \(x^2-x-xy-2y^2+2y\)
2/ \(G=4\dfrac{7}{5741}.\dfrac{1}{3759}-\dfrac{4}{3759}.1\dfrac{2}{5741}+\dfrac{1}{3759}+\dfrac{1}{3759.5741}_{ }\)
Phân tích đa thức thành nhân tử
1/ xy(x-y)+yx(y-z)+zx(z-x)
\(xy\left(x-y\right)+yz\left(y-z\right)+xz\left(z-x\right)\\ =xy\left(x-y\right)+yz\left[-\left(x-y\right)-\left(z-x\right)\right]+xz\left(z-x\right)\\ =xy\left(x-y\right)-yz\left(x-y\right)-yz\left(z-x\right)+xz\left(z-x\right)\\ =\left(x-y\right)\left(xy-yz\right)+\left(z-x\right)\left(xz-yz\right)\\ =y\left(x-y\right)\left(x-z\right)+z\left(z-x\right)\left(x-y\right)\\ =\left(x-y\right)\left(x-z\right)\left(y-z\right)\)
\(G=4\frac{7}{5741}.\frac{1}{3759}-\frac{4}{3759}.1\frac{2}{5741}+\frac{1}{3759}+\frac{1}{3759.5741}\)
tính
\(1\frac{7}{5741}.\frac{1}{3759}-\frac{4}{3741}.1\frac{2}{5741}+\frac{1}{3759}+\frac{1}{3759.5741}\)
Tính :
1 . F = 5\(\dfrac{6}{4453}\). \(\dfrac{1}{1997}\)- \(\dfrac{2}{1997}.2\dfrac{3}{4453}\)
2 . G = 4\(\dfrac{7}{5741}\).\(\dfrac{1}{3759}\) - \(\dfrac{4}{3759}\). 1\(\dfrac{2}{5741}\)+ \(\dfrac{1}{3759}\)+ \(\dfrac{1}{3759.5741}\)
Đặt tính rồi tính
2 289 x 4
63 750 : 5
63 740 + 3759
100 000 - 73 783
(4568+3759)_(4563+3759)=?
(4568 + 3759) - (4563 + 3759)
= 4568 + 3759 - 4563 - 3759
= 3
Làm lại
(4568 + 3759) - (4568 + 3759)
= 4568 + 3759 - 4563 + 3759
= 5
Lộn nữa
(4568 + 3759) - (4563 + 3759)
= 4568 + 3759 - 4563 + 3759
= 5
Đặt tính rồi tính:
63740 + 3759
tính thuận tiện nhất :
3759 - 642 - 117
tính thuận tiện nhất :
3759 - 642 - 117
= 3759 - ( 642 - 117 )
= 3759 - 525
= 3234.