Tính A=\(2\frac{1}{315}\).\(\frac{1}{651}\)- \(\frac{1}{105}\).\(3\frac{650}{651}\)- \(\frac{4}{315.651}\)+ \(\frac{4}{105}\)
\(2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
\(=\left(2+\frac{1}{315}\right).\frac{1}{651}-\frac{1}{105}.\left(3+\frac{650}{651}\right)-\frac{4}{315.651}+\frac{4}{105}\)
\(=2.\frac{1}{651}+\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3+\frac{1}{105}.\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
\(=\frac{2}{651}+\frac{1}{315.651}-\frac{3}{105}-\frac{650}{105.651}-\frac{4}{315.651}+\frac{4}{105}\)
\(=\frac{2}{615}+\left(\frac{1}{315.651}-\frac{4}{315.651}\right)+\left(\frac{-3}{105}+\frac{4}{105}\right)-\frac{650}{105.651}\)
\(=\frac{2}{651}-\frac{3}{315.651}+\frac{1}{105}-\frac{650}{105.651}\)
\(=\left(\frac{2}{651}+\frac{1}{105}\right)-\frac{650}{105.651}-\frac{3}{315.651}\)
\(=\left(\frac{2.105}{105.651}+\frac{651}{105.651}\right)-\frac{650}{105.651}-\frac{3}{315.651}\)
\(=\frac{211}{105.651}-\frac{3}{315.651}\)
\(=\frac{1}{651}.\left(\frac{211}{105}-\frac{3}{315}\right)\)
\(=\frac{1}{651}.\left(\frac{633}{315}-\frac{3}{315}\right)\)
\(=\frac{1}{651}.2\)
\(=\frac{2}{651}\)
Tính \(A=2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
Đặt \(a=\frac{1}{315}\), \(b=\frac{1}{651}\)ta có :
\(A=\left(2+a\right)\cdot b-3a\left(3+1-b\right)-4ab+12a\)
\(\Rightarrow A=2b+ab-12a+3ab-4ab+12a\)
\(\Rightarrow A=2b=\frac{2}{651}\)
tính nhanh:
C=\(2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
\(C=\frac{631}{315}.\frac{1}{651}-\frac{1}{103}.\frac{2603}{651}-\frac{4}{315}.\frac{1}{651}+\frac{4}{105}\)
\(=\frac{1}{651}.\left(\frac{631}{315}-\frac{4}{315}\right)+\frac{2603}{68355}+\frac{4}{105}\)
\(=\frac{1}{651}.\frac{209}{105}+\frac{2603}{68355}+\frac{4}{105}\)
\(=\frac{1}{105}.\left(\frac{209}{651}+\frac{4}{105}\right)+\frac{2603}{68355}\)
\(=105.\frac{167}{465}+\frac{2603}{68355}\)
\(=\frac{1169}{31}+\frac{2603}{68355}=37,74775803\)
Tính nhanh và gọn hết cỡ đc có vậy thôi. Bạn xem lại đề bài nhé
\(C=2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
\(C=\left(2+\frac{1}{315}\right).\frac{1}{651}-3.\frac{1}{315}.\left(4-\frac{1}{651}\right)-4.\frac{1}{315}.\frac{1}{651}+12.\frac{1}{315}\)
Đặt \(\frac{1}{315}=x;\frac{1}{651}=y\),khi đó C trở thành:
\(C=\left(2+x\right).y-3x.\left(4-y\right)-4xy+12y\)
\(C=2y+xy-12x+3xy-4xy+12x\)
\(C=2y=2.\frac{1}{651}=\frac{2}{651}\)
Vậy C=2/651
Tính nhanh
\(2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
\(\left(2+\frac{1}{315}\right).\frac{1}{651}-\frac{1}{105}\left(3+1-\frac{1}{651}\right)-\frac{4}{315.651}+\frac{4}{105}\)
\(=\frac{2}{651}+\frac{1}{315.651}-\frac{4}{105}+\frac{1}{105.651}-\frac{4}{315.651}+\frac{4}{105}\)
\(=\frac{2}{651}-\frac{3}{315.651}+\frac{1}{105.651}\)
\(=\frac{2}{651}-\frac{1}{105.651}+\frac{1}{105.651}=\frac{2}{651}\)
\(2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
Bài 1: Tính giá trị biểu thức:
\(A=2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
\(A=2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
\(A=\left(2+\frac{1}{315}\right).\frac{1}{651}-3.\frac{1}{315}.\left(4-\frac{1}{651}\right)-4.\frac{1}{315}.\frac{1}{651}+12.\frac{1}{315}\)
Đặt \(\frac{1}{315}=x;\frac{1}{651}=y\),khi đó:
\(A=\left(2+x\right)y-3x\left(4-y\right)-4xy+12y\)
\(A=2y+xy-12x+3xy-4xy+12y=2y=2.\frac{1}{651}=\frac{2}{651}\)
Vậy A=2/651
A=\(2.\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
Tính \(A=2\frac{1}{315}.\frac{1}{615}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
Tính: \(C=2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}+\frac{4}{105}\)
\(E=2\frac{1}{315}.\frac{1}{651}-\frac{1}{105}.3\frac{650}{651}-\frac{4}{315.651}-\frac{4}{105}\)=?