Tìm x , biết :
1) 1/4 + 3/4.x = 1/2
2) x/5 +x/10=2/5
3)x-2/3 = 5/7
4) 2.x – 1 / 6 = x-3/2
5) ( 75% . x – 2/3 ) = 1/6
Tìm x , biết : 1) 1/4 + 3/4.x = 1/2 2) x/5 +x/10=2/5 3)x-2/3 = 5/7 4) 2.x – 1 / 6 = x-3/2 5) ( 75% . x – 2/3 ) = 1/6
By Remi
By Remi
Tìm x , biết :
1) 1/4 + 3/4.x = 1/2
2) x/5 +x/10=2/5
3)x-2/3 = 5/7
4) 2.x – 1 / 6 = x-3/2
5) ( 75% . x – 2/3 ) = 1/6
1)1/4 + 3/4.x = 1/2
3/4.x = 1/2-1/4
3/4.x – 1/4
x = 1/4:3/4
x=1/3
2)x/5 +x/10=2/5
2x/10+x/10=4/10
=>3x=4
x=4/3
3)x-2/3 = 5/7
x =5/7+2/3
x=29/21
4)2.x – 1 / 6 = x-3/2
2.x=x-3/2+1/6
2.x=x-5/3
=>x-2x=5/3
=>-x=5/3
=>x=-5/3
5) ( 75% . x – 2/3 ) = 1/6
3/4.x-2/3=1/6
3/4-x=1/6+2/3
3/4.x=5/6
x=5/6:3/4
x=10/9
Đáp án + giải thích bước giải :
`1) 1/4 + 3/4x = 1/2`
`-> 3/4x = 1/2 – 1/4`
`-> 3/4x = 1/4`
`-> x = 1/4 : 3/4`
`-> x = 1/3`
Vậy `x = 13`
`2) x/5 + x/10 = 2/5`
`->x . (1/5 + 1/10) = 2/5`
`-> x . 3/10 = 2/5`
`-> x = 2/5 : 3/10`
`-> x = 4/3`
Vậy `x = 4/3`
`3) x – 2/3 = 5/7`
`-> x = 5/7 + 2/3`
`-> x = 29/21`
Vậy `x = 29/21`
`4) 2x – 1/6 = x – 3/2`
`-> 2x – x = 1/6 – 3/2`
`-> (2 – 1)x = (-4)/3`
`-> x = (-4)/3`
Vậy `x = (-4)/3`
`5) (75%x – 2/3) = 1/6`
`-> 3/4x = 1/6 + 2/3`
`-> 3/4x = 5/6`
`-> x = 5/6 : 3/4`
`-> x = 10/9`
Vậy `x = 10/9`