[tex] \frac{10 {x}^{3} + 6( {x}^{2} - 2) }{2} - 2x(3 - 2x - {x}^{2}) = \frac{10 {x}^{3} + 6 {x}^{2} - 12}{2} - 6x + 4 {x}^{2} + 2 {x}^{3} = 5 {x}^{3} + 3 {x}^{2} - 6 - 6x + 4 {x}^{2} + 2 {x}^{3} = 7 {x}^{3} + 7 {x}^{2} - 6x - 6 = 7 {x}^{2}(x + 1) - 6(x + 1) [/tex]