Đáp án:
Giải thích các bước giải:
`a) 2/3 . x - 4/7 = 1/14 `
` 2/3.x = 1/14 + 4/7 `
`2/3.x=9/14 `
`x=9/14 : 2/3 `
`x=27/28 `
vậy `x = 27/28 `
` ( 4,5 - 2x).(-14/7) = 11/14 `
` 9/2 - 2x = 11/14 : -14/7 `
` 9/2 - 2x = -11/27 `
` 2x = 9/2 - (-11)/27 `
` 2x = 265/54 `
` x = 265/54 : 2 `
`x=265/108 `
vậy `x = 265/108 `
` 1/12 . x - 75% = 12/3 `
` 1/12 . x - 3/4 = 12/3 `
` 1/12 . x = 12/3 + 3/4 `
`1/12 . x = 19/4 `
` x = 19/4 : 1/12 `
`x=57 `
vậy `x = 57 `
` (( -2x)/5 + 1 ) : -5 = -1/25 `
` (-2x)/5 + 1 = -1/25 . -5 `
` (-2x)/5 + 1 = 1/5 `
` (-2x)/5 = 1/5 + 1 `
` (-2x)/5 = 6/5 `
` -2x.5 = 6.5 `
` -2x.5 = 30 `
` -2x = 30 :5 `
` -2x = 6 `
` x = 6 : -2 `
`x=-3 `
vậy `x = -3 `
