Ответ:

[tex]1)(5 {x}^{2} + 6x - 3) - (2 {x}^{2} - 3x - 4) = 5 {x}^{2} + 6x - 3 - 2 {x}^{2} + 3x + 4 = 3 {x}^{2} + 9x + 1 \\ 2) - 4 {a}^{2} ( {a}^{3} - a + 4) = - 4 {a}^{5} + 4 {a}^{3} - 16 {a}^{2} = - {a}^{2} - 16 {a}^{2} \\ 3)(4x - 3)(x + 1) = 4 {x}^{2} + 4x - 3x - 1 = 4 {x}^{2} + x - 1 \\ 4)(x - 6)( {x}^{2} + 2x - 3) = {x}^{3} - 2 {x}^{2} - 3x - 6 {x}^{2} - 12x + 18 = {x}^{3} - 8 {x}^{2} - 15x + 18[/tex]