[tex]\Huge \mid \underline {\mathcal {{{\color{indigo}{Answer...}}}}} \mid[/tex]
[tex]{{ \large{ \blue{ \rm{{↬}}}}}} \rm \large \: \:(x+1) (x²+3x-4)[/tex]
[tex]{{ \large{ \blue{ \rm{{↬}}}}}} \rm \large \: \:x( {x}^{2} + 3x - 4) \: + \: 1( {x}^{2} + 3x - 4)[/tex]
[tex]{{ \large{ \blue{ \rm{{↬}}}}}} \rm \large \: \: {x}^{3} + {3x}^{2} - 4x + {x}^{2} + 3x - 4[/tex]
[tex]{{ \large{ \blue{ \rm{{↬}}}}}} \rm \large \: \: {x}^{3} + \: {4x}^{2} - x - 4[/tex]