`(x-10)x11=22`
`x - 10 = 22 : 11`
`x - 10 = 2`
`x = 2 +10 `
`x= 12`
`2x+15=27`
`2x = 27 - 15`
`2x = 12`
`x = 12 : 2`
`x = 6`
`(-765)-(305+x)=100`
`(305 + x ) = ( - 765 ) - 100`
`(305 + x ) = - 865`
` x = - 865 - 305`
`x= -1170`
$2^{x}$ ` : 4 = 16`
$2^{x}$ `= 16 . 4`
$2^{x}$ `= 64`
`x` = ` 2^6`
`x` = `6`