Question

1. Tìm x a) 30 - 5 × x = 5 b) 6 + 4 : x = 10 c) 20/x = 8/12

Answer 1

`a)30-5 xx x=5`

`5 xx x=30-5`

`5 xx x=25`

`x=25:5`

`x=5`

`b)6+4:x=10`

`4:x=10-6`

`4:x=4`

`x=4:4`

`x=1`

`c)20/x=8/12`

`x xx 8=20xx12`

`x xx 8=240`

`x=240:8`

`x=30`

Answer 2

a: =>5x=30-5=25

=>x=5

b: =>4:x=10-6=4

=>x=1

c: =>20/x=2/3

hay x=30

Answer 3

\(a.30-5\times x=5\)

\(25\times x=5\)

\(x=25:5\)

\(x=5\)

\(b.6+4:x=10\)

\(10:x=10\)

\(x=10:10\)

\(x=1\)

\(c.\dfrac{20}{x}=\dfrac{8}{12}\)

\(x=20:8\)

\(x=2,5\)

\(x=2,5\times12\)

\(x=30\)

Answer 4

a/ 30 - 5 x \(x\) = 5

    30 - 5 = \(x\) : 5

    25 = \(x\) : 5

    \(x\) = 25 : 5

    \(x\) = 5

b/ 6 + 4 : \(x\) = 10

    6 + 4 =  \(x\) x 10

    10 = \(x\) x 10

    \(x\) = 10 : 10

    \(x\) = 1

c/ \(\dfrac{20}{x}=\dfrac{8}{12}\)

    \(\dfrac{20}{x}=\dfrac{20}{30}\)

→ \(x\) = 30