Let the number be X, then we find
[tex]( {x}^{2} - 8) \div 7 + 12 = 20[/tex]
[tex]( {x}^{2} - 8) \div 7 = 8[/tex]
[tex]( {x}^{2} - 8) = 56[/tex]
[tex] {x}^{2} = 64[/tex]
[tex]x = \sqrt{64} \: \: \: \: \: x = - \sqrt{64} [/tex]
[tex]x = 8 \: \: \: \: \: x = - 8[/tex]
