`[ ( 2 xx x - 11 ) : 3 + 1 ] xx 5 = 20`
`( 2 xx x - 11 ) : 3 + 1=20:5`
`( 2 xx x - 11 ) : 3 + 1=4`
`( 2 xx x - 11 ) : 3 =4-1`
`( 2 xx x - 11 ) : 3 =3`
`2xx x -11=3xx3`
`2xx x -11=9`
`2xx x =9+11`
`2 xx x=20`
`x=20:2`
`x=10`
Vậy `x=10`
`b, x - 96 = ( 443 - x ) - 15`
`x-96=443-x-15`
` x+x=443-15+96`
`2x=524`
`x=524:2`
`x= 262`
Vậy `x=262`
\(#Nqoc\)
`a)`
\([ ( 2 \times x - 11 ) \div 3 + 1 ] \times 5 = 20\)
`(2 \times x - 11) \div 3 + 1 = 20 \div 5`
`(2 \times x - 11) \div 3 + 1 = 4`
`(2 \times x - 11) \div 3 = 4 - 1`
`(2 \times x - 11) \div 3 = 3`
`2 \times x - 11 = 3 \times 3`
`2 \times x - 11 = 9`
`2 \times x = 9 + 11`
`2 \times x = 20`
`x = 20 \div 2`
`x = 10`
Vậy, `x = 10`
`b)`
\(x - 96 = ( 443 - x ) - 15\)
`x - 96 = 443 - x - 15`
`x - 96 = 428 - x`
`x = 428 - x + 96`
`x = 524 - x`
`x - 524 + x = 0`
`(x + x) - 524 = 0`
`2x - 524 = 0`
`2x = 524`
`x = 524 \div 2`
`x = 262`
Vậy, `x = 262.`
