Question

Tìm x, biết :

a. 1/² + x = 3/⁴

b. 5/² - x = 1/³

c. 2. ( 1/³ + x ) = 1/⁵

d. 2/³ - ( 1/² - x ) = 1/⁵

Answer 1

`a, 1/2 +x=3/4`

`=> x= 3/4 -1/2`

`=> x= 3/4-2/4`

`=>x= 1/4`

`b, 5/2 -x=1/3`

`=> x= 5/2 -1/3`

`=> x= 15/6 - 2/6`

`=>x= 13/6`

`c, 2 . (1/3 +x)=1/5`

`=> 1/3 +x=1/5:2`

`=> 1/3 +x= 1/10`

`=>x= 1/10-1/3`

`=>x= 3/30 - 10/30`

`=>x=-7/30`

`d, 2/3 - (1/2 -x)=1/5`

`=> 1/2-x= 2/3 -1/5`

`=>1/2-x= 10/15 - 3/15`

`=>1/2-x=7/15`

`=>x= 1/2-7/15`

`=>x=1/30`

Answer 2

`1/2 + x = 3/4`

`=>    x  = 3/4 - 1/2`

`=>    x   = 1/4`

`5/2 - x  = 1/3`

`=>    x  =  5/2 - 1/3`

`=>    x  = 13/6`

`2.(1/3 + x) = 1/5`

`=>1/3 + x  = 1/10 `

`=>         x =  1/10 - 1/3`

`=>        x   = -7/30`

`2/3 - (1/2 -x)= 1/5`

`=>     1/2 - x = 7/15`

`=>             x  = 1/2 - 7/15`

`=>             x  = 1/30`

Answer 3

a. \(\dfrac{1}{2}+x=\dfrac{3}{4}\)

⇔ \(x=\dfrac{3}{4}-\dfrac{1}{2}\)

⇔ \(x=\dfrac{1}{4}\)

b. \(\dfrac{5}{2}-x=\dfrac{1}{3}\)

⇔ \(-x=\dfrac{1}{3}-\dfrac{5}{2}\)

⇔ \(-x=-\dfrac{13}{6}\)

⇔ \(x=\dfrac{13}{6}\)

c. \(2\left(\dfrac{1}{3}+x\right)=\dfrac{1}{5}\)

⇔ \(\dfrac{1}{3}+x=\dfrac{1}{5}\div2\)

⇔ \(x=\dfrac{1}{10}-\dfrac{1}{3}\)

⇔ \(-\dfrac{7}{30}\)

d. \(\dfrac{2}{3}-\left(\dfrac{1}{2}-x\right)=\dfrac{1}{5}\)

⇔ \(-\dfrac{1}{2}+x=\dfrac{1}{5}-\dfrac{2}{3}\)

⇔ \(x=-\dfrac{7}{15}+\dfrac{1}{2}\)

⇔ \(x=\dfrac{1}{30}\)

 

Answer 4

a: 1/2+x=3/4

=>x=3/4-1/2=3/4-2/4=1/4

b: 5/2-x=1/3

=>x=5/2-1/3=15/6-2/6=13/6

c: =>x+1/3=1/5:2=1/10

=>x=1/10-1/3=-7/30

d: =>1/2-x=2/3-1/5=10/15-3/15=7/15

=>x=1/2-7/15=15/30-14/30=1/30