`1/`
`a)| -525|-(-635)-475-(525+635)`
`⇔525+635-475-525-635`
`⇔(525-525)+(635-635)-475`
`⇔-475`
`b)15.(-24)+(-24).84-24`
`⇔-24.(15+84+1)`
`⇔-24.100`
`⇔-2400`
`c)27.(-16)+(-16).74+16`
`⇔-16.(27+74-1)`
`⇔-16.100`
`⇔-1600`
`2/`
`a)2(x+4)-16=98+x`
`⇔2x+8-16=98+x`
`⇔2x-x=98+16-8`
`⇔x=106`
`b)(6x-18)(4x-24)=0`
`⇔` \(\left[ \begin{array}{l}6x-18=0\\4x-24=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}6x=18hoặc \\4x=24\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=3 hoặc \\x=6\end{array} \right.\)
`c)(5x+45)(7-x)-1=-1`
`⇔(5x+45)(7-x)=0`
`⇔` \(\left[ \begin{array}{l}5x+45=0 hoặc \\x=7-x=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}5x=-45 hoặc\\x=7\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=-9 hoặc \\x=7\end{array} \right.\)
