[tex]\tt{} {2x}^{2} - 26x + 84[/tex]
[tex]\tt{}2 {(x}^{2} - 13x + 42)[/tex]
[tex]\tt{}2 {(x}^{2} - 6x - 7x + 42)[/tex]
[tex]\tt{}2( x \times (x - 6) - 7(x - 6))[/tex]
[tex]\tt{}2(x - 6) \times (x - 7)[/tex]
