bai1 A, -7/18+4/9–5/12 B, (1 1/5-2/3):(2 2/5+1/3) C,-3/29+8/45+-26/29+37/45
bai2 A, x-4 1/5=-2/3 B.-2 1/9.(x-7 1/3)=1,5
bai1 A, -7/18+4/9–5/12 B, (1 1/5-2/3):(2 2/5+1/3) C,-3/29+8/45+-26/29+37/45
bai2 A, x-4 1/5=-2/3 B.-2 1/9.(x-7 1/3)=1,5
Đáp án:
Giải thích các bước giải:
1.
`A, -7/18+4/9–5/12`
` = 1/18 – (-5/12)`
` = 17/36 `
`B, (1 1/5-2/3): ( 2 2/5 + 1/3 ) `
` = ( 6/5 – 2/3 ) 🙁 12/5 + 1/3 ) `
` = 8/15 : 41/15 `
` = 8/41 `
`C,-3/29+8/45+(-26)/29+37/45`
` = ( -3/29 + (-26)/29 ) + ( 8/45 + 37/45 ) `
` = -1 + 1 `
` = 0 `
2.
`A, x-4 1/5=-2/3`
` x – 21/5 = -2/3 `
`x = -2/3 + 21/5 `
`x = 53/15 `
vậy `x = 53/15 `
`B.-2 1/9.(x-7 1/3)=1,5`
` -19/9 . ( x – 22/3) = 3/2 `
` x – 22/3 = 3/2 : ( -19)/9 `
`x – 22/3 = -27/38`
`x = -27/38 + 22/3 `
`x = 755/114 `
vậy `x = 755/114 `
Đáp án + Giải thích các bước giải:
Bài `1:`
a)
`-7/18 + 4/9 – -5/12`
`= -7/18 + 4/9 + 5/12 = -14/36 + 16/36 + 15/36`
`= (-14+16+15)/36 = 17/36`
b)
`( 1 1/5 – 2/3 ) : ( 2 2/5 + 1/3 )`
`= ( 6/5 – 2/3 ) : ( 12/5 + 1/3 )`
`= 8/15 : 41/15 = 8/15 . 15/41 = 8/41`
c)
`(-3)/29 + 8/45 + (-26)/29 + 37/45`
`= (-3)/29 + (-26)/39 + 8/45 + 37/45`
`= (-39)/39+ 45/45 = (-1) + 1 = 0`
Bài `2:`
a)
`x – 4 1/5 = -2/3`
`to x – 21/5 = -2/3`
`to x = -2/3 + 21/5`
`to x = 53/15`
Vậy `x = 53/15`
b)
`-2 1/9 . ( x – 7 1/3 ) = 1,5`
`to -19/9 . ( x – 22/3 ) = 3/2`
`to x – 22/3 = 3/2 : (-19/9)`
`to x – 22/3 = -27/38`
`to x = -27/38 + 22/3`
`to x = 755/114`
Vậy `x = 755/114`