tìm x `a)2/5+3/4:x=-1/2` `b)5/7-2/3.x=4/5` `c)1/2x+3/5x=-2/3` `d)4/7x-x=\frac{-9}{14}`
2 câu trả lời
Đáp án + Giải thích các bước giải:
`a)2/5+3/4` `:` `x=-1/2`
`3/4` `:` `x=-1/2-2/5`
`3/4` `:` `x=-9/10`
`x=3/4:(-9/10)`
`x=-5/6`
Vậy `x=-5/6`
`b)5/7-2/3` `.` `x=4/5`
`2/3` `.` `x=5/7-4/5`
`2/3` `.` `x=-3/35`
`x=(-3/35):2/3`
`x=-9/70`
Vậy `x=-9/70`
`c)1/{2}x+3/{5}x=-2/3`
`(1/2+3/5)x=-2/3`
`11/10` `x=-2/3`
`x=(-2/3):11/10`
`x=-20/33`
Vậy `x=-20/33`
`d)4/{7}x-x=-9/14`
`(4/7-1)x=-9/14`
`-3/{7}x=-9/14`
`x=-9/14` `:` `(-3/7)`
`x=3/2`
Vậy `x=3/2`
Giải thích các bước giải:
`a) 2/5+3/4:x=-1/2`
`=>3/4:x=(-1/2)-2/5`
`=>3/4:x=-9/10`
`=>x=3/4:(-9/10)`
`=>-5/6`
Vậy `x=-5/6`
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`b) 5/7-2/3 .x=4/5`
`=>2/3 .x=5/7-4/5`
`=>2/3 .x=-3/35`
`=>x=(-3/35):2/3`
`=>x=-9/70`
Vậy `x=-9/70`
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`c) (1/2 )x+(3/5)x=-2/3`
`=>x(1/2+3/5)=-2/3`
`=>x. (11/10)=-2/3`
`=>x=(-2/3):11/10`
`=>x=-20/33`
Vậy `x=-20/33`
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`d) (4/7)x-x=-9/14`
`=>x(4/7-1)=-9/14`
`=>x. (-3/7)=-9/14`
`=>x=(-9/14):(-3/7)`
`=>x=3/2`
Vậy `x=3/2`
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