Write the relation given in statement as follows.
[tex](x-1)(x+2)=70[/tex]On solving this,
[tex]\begin{gathered} x^2-x+2x-2=70 \\ x^2+x-2-70=0 \\ x^2+x-72=0 \end{gathered}[/tex]Write this equation as (x+9)(x-8)=0
Hence the solution set is
[tex]\mleft\lbrace-9,8\mright\rbrace[/tex]