[tex] {\qquad\qquad\huge\underline{{\sf Answer}}} [/tex]
Here we go ~
[tex]\qquad \sf \dashrightarrow \: (f + g)(x)[/tex]
[tex]\qquad \sf \dashrightarrow \: f(x) + g(x)[/tex]
[tex]\qquad \sf \dashrightarrow \: (4 {x}^{2} - 5x) + (3 {x}^{2} + 6x - 4)[/tex]
[tex]\qquad \sf \dashrightarrow \: 7 {x}^{2} + x - 4[/tex]
