Thực hiện phép tính A/ 10/21 × -14/3 + 5/9 B/ 7/8 × 7/13 + 7/8 × 9/13 – 7/8 × 3/13 13/09/2021 Bởi Amara Thực hiện phép tính A/ 10/21 × -14/3 + 5/9 B/ 7/8 × 7/13 + 7/8 × 9/13 – 7/8 × 3/13
`a ) 10/21 xx` `\frac{-14}{3}` `+ 5/9` `=` `\frac{-140}{63}` `+ 5/9` `=` `\frac{-140}{63}` `+ 35/63 =` `\frac{-105}{63}` `=` `\frac{-15}{9}` `b ) 7/8 xx 7/13 + 7/8 xx 9/13 – 7/8 xx 3/13` `= 7/8 . (7/13 + 9/13 – 3/13 )` `= 7/8. 13/13` `= 91/104 = 7/8` `\text{Từng đã làm}` Bình luận
`a ) 10/21 xx` `\frac{-14}{3}` `+ 5/9`
`=` `\frac{-140}{63}` `+ 5/9`
`=` `\frac{-140}{63}` `+ 35/63 =` `\frac{-105}{63}` `=` `\frac{-15}{9}`
`b ) 7/8 xx 7/13 + 7/8 xx 9/13 – 7/8 xx 3/13`
`= 7/8 . (7/13 + 9/13 – 3/13 )`
`= 7/8. 13/13`
`= 91/104 = 7/8`
`\text{Từng đã làm}`
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