6.
[tex] {a}^{2} - 11a + 30[/tex]
**30=6×5
[tex] {a}^{2} - 5a - 6a + 30[/tex]
[tex]a(a - 5) - 6(a - 5)[/tex]
[tex](a - 5)(a - 6)[/tex]
8.
[tex] {x}^{2} + 4x - 45[/tex]
**45=9×5
[tex] {x}^{2} + 9x - 5x - 45[/tex]
[tex]x(x + 9) - 5(x + 9)[/tex]
[tex](x + 9)(x - 5)[/tex]
