Answer:
[tex]3 {x}^{2} + 5x - 7x + 3 - 5 {x}^{2} + 2 \\ 3 {x}^{2} - 5 {x}^{2} + 5x - 7x + 3 + 2 \\ = - 2 {x}^{2} - 2x + 5[/tex]