`( 42 - x ) : 9 + 1 = 4`
`( 42 - x ) : 9 =4-1`
`( 42 - x ) : 9 =3`
`42-x=3xx9`
`42-x=27`
`x=42-27`
`x=15`
Vậy `=15`
`55 - 5 xx ( x + 1 ) = 20`
`5 xx ( x + 1 ) =55-20`
`5 xx ( x + 1 ) =35`
`x+1=35:5`
`x+1=7`
`x=7-1`
`x=6`
Vậy `x=6`
`164 - 64 : ( 12 + x ) = 160`
` 64 : ( 12 + x ) =164-160`
` 64 : ( 12 + x ) =4`
`12+x=64:4`
`12+x=16`
`x=16-12`
`x=2`
Vậy `x=2`
`@` `\text {Ans}`
`\downarrow`
`(42 - x) \div 9 + 1 = 4`
` (42 - x) \div 9 = 4 - 1`
` (42 - x) \div 9 = 3`
` 42 - x = 3 \times 9`
` 42 - x = 27`
` x = 42 - 27`
` x = 15`
______
`55 - 5 \times ( x + 1 ) = 20`
`5 \times (x+1) = 55 - 20`
`5 \times (x+1) = 35`
`x + 1 = 35 \div 5`
`x + 1 = 7`
`x = 7 - 1`
`x = 6`
______
`164 - 64 \div ( 12 + x ) = 160`
`64 \div (12 + x) = 164 - 160`
`64 \div (12 + x) = 4`
`12 + x = 64 \div 4`
`12 + x = 16`
`x = 16 - 12`
`x = 4`
`@` `\text {Kaizuu lv uuu}`
\(\left(42-x\right):9+1=4\)
\(\left(42-x\right):9=4-1\)
\(\left(42-x\right):9=3\)
\(42-x=3\times9\)
\(42-x=27\)
\(x=42-27\)
\(x=15\)
\(55-5\times\left(x+1\right)=20\)
\(5\times\left(x+1\right)=55-20\)
\(5\times\left(x+1\right)=35\)
\(x+1=35:5\)
\(x+1=7\)
\(x=7-1\)
\(x=6\)
\(164-64:\left(12+x\right)=160\)
\(64:\left(12+x\right)=164-160\)
\(64:\left(12+x\right)=4\)
\(12+x=64:4\)
\(12+x=16\)
\(x=16-12\)
\(x=4\)
( 42 - x ) : 9 + 1 = 4
(42 - x): 9 = 4-1
(42-x):9=3
(42-x)= 3 x 9
42 - x= 27
x= 42 - 27
x=15
___
55 - 5 x ( x + 1 ) = 20
5 x (x+1)= 55 - 20
5 x (x+1)= 35
x+1= 35:5
x+1=7
x=7-1
x=6
________
164 - 64 : ( 12 + x ) = 160
64 : (12+x)= 164 - 160
64:(12+x)=4
12+x= 64:4
12+x=16
x=16-12
x=4
