[tex]4)4(2 - x) - 5(3x + 6)[/tex]
[tex] = 8 - 4x - 15x - 30[/tex]
[tex] = - 19x - 22[/tex]
[tex]5)3 {x}^{3} - 27x = 3x( {x}^{2} - 9)[/tex]
[tex] = 3x(x - 3)(x + 3)[/tex]
[tex]6) \frac{ 3\sqrt{2} }{4 \sqrt{3} - 6} = \frac{3 \sqrt{2} (4 \sqrt{3} + 6)}{(4 \sqrt{3} - 6)(4 \sqrt{3} + 6) } [/tex]
[tex] = \frac{12 \sqrt{6} + 18 \sqrt{2} }{ {(4 \sqrt{3}) }^{2} - {6}^{2} } = \frac{12 \sqrt{6} + 18 \sqrt{2} }{48 - 36} [/tex]
[tex] = \frac{6(2 \sqrt{6} + 3 \sqrt{2} )}{12} = \frac{2 \sqrt{6} + 3 \sqrt{2} }{2} [/tex]