Giải thích các bước giải:
`(x^2-5)(x+3)=0`
`=>`\(\left[ \begin{array}{l}x^2-5=0\\x+3=0\end{array} \right.\) `=>`\(\left[ \begin{array}{l}x^2=5\\x=-3\end{array} \right.\) `=>`\(\left[ \begin{array}{l}x=\pm\sqrt5\\x=-3\end{array} \right.\)
`(x-12)/77+(x-11)/78=(x-74)/15+(x-73)/16`
`=>((x-12)/77-1)+((x-11)/78-1)=((x-74)/15-1)+((x-73)/16-1)`
`=>(x-89)/77+(x-89)/78=(x-89)/15+(x-89)/16`
`=>(x-89)/77+(x-89)/78-(x-89)/15-(x-89)/16=0`
`=>(x-89)(1/77+1/78-1/15-1/16)=0`
Mà `1/77+1/78-1/15-1/16 ne 0`
`=>x-89=0=>x=89`
