The area of the rectangle is of the form 6x² - 9x - 15
Factoring the given expression,
[tex] \sf \: {6x}^{2} - 9x - 15 \\ \\ \leadsto \: \sf \: 3\bigg( {2x}^{2} - 3x - 5 \bigg) \\ \\ \leadsto \: \sf \: 3 \bigg( {2x}^{2} - 5x + 2x - 5 \bigg) \\ \\ \leadsto \: \sf \: 3 \bigg((2x - 5)(x + 1) \bigg)[/tex]
Length of the rectangle is 2x - 5
Thus,
[tex] \leadsto \: \sf \: (2x - 5)(3x + 3)[/tex]