Đáp án+Giải thích các bước giải:
Bài 2:
`2.1) 3/4x-2/3x=1/2`
`<=> (3/4-2/3)x=1/2`
`<=> (9/(12)-8/(12))x=1/2`
`<=> 1/12x=1/2`
`<=> x =1/2:1/(12)`
`<=> x = 1/2 . 12`
`<=> x = 6`
Vậy `x=6`
`2.2) x-5/3x=(22)/9`
`<=> (1-5/3)x=(22)/9`
`<=> (3/3-5/3)x=(22)/9`
`<=> (-2)/3x=(22)/9`
`<=> x =(22)/9:(-2)/3`
`<=> x = (22)/9 . (-3)/2`
`<=> x = -(11)/3`
Vậy `x = -(11)/3`
`2.3) 3x=75%x-1,2`
`<=> 3x = 3/4x-6/5`
`<=> 3x - 3/4x=-6/5`
`<=> (3-3/4)x=-6/5`
`<=> ((12)/4-3/4)x=-6/5`
`<=> 9/4x=-6/5`
`<=> x = (-6)/5:9/4`
`<=> x = (-6)/5 . 4/9`
`<=> x = -8/(15)`
Vậy `x = -8/(15)`
`2.4) x-1/5x=-1 1/5`
`<=> (1-1/5)x=(-6)/5`
`<=> (5/5-1/5)x=(-6)/5`
`<=> 4/5x = -6/5`
`<=> x =(-6)/5 : 4/5`
`<=> x = (-6)/5 . 5/4`
`<=> x (-3)/2`
Vậy `x=-3/2`
`2.5) 3/4x=2/3x+1/2`
`<=> 3/4x-2/3x=1/2`
`<=> (3/4-2/3)x=1/2`
`<=> (9/(12)-8/(12))x=1/2`
`<=> 1/(12)x=1/2`
`<=> x =1/2:1/(12)`
`<=> x = 1/2 . 12`
`<=> x = 6`
Vậy `x=6`
`2.6) 5/7x-x=1 1/7`
`<=> (5/7-1)x=8/7`
`<=> (5/7-7/7)x=8/7`
`<=> (-2)/7x = 8/7`
`<=> x = 8/7:(-2)/7`
`<=> x = 8/7 . (-7)/2`
`<=> x = -4`
Vậy `x=-4`
