$\text{Đáp án + Giải thích các bước giải:}$
`\text{Bài 1:}`
`a//-2009-(234-|-2009|)`
`=-2009-(234-2009)`
`=-2009-234+2009`
`=(2009-2009)-234`
`=0-234`
`=-234`
`b//4^{2}-(-11)+(-3)^{3}`
`=16+11+(-27)`
`=27-27`
`=0`
`c//77.(23+27)-23.(77-27)`
`=77.23+77.27-23.77+23.27`
`=(77.23-23.77)+(77.27+23.27)`
`=0+27.(77+23)`
`=27.100`
`=2700`
`\text{Bài 2:}`
`a//15-(13+x)=17`
`=>15-13-x=17`
`=>2-x=17`
`=>x=2-17`
`=>x=-15`
`b//4x-15=-75-x`
`=>4x+x=15-75`
`=>5x=-60`
`=>x=-12`
`c//(-14)/(x)=(35)/(20)`
`=>35x=-14.20`
`=>35x=-280`
`=>x=-8`
