[tex]8x^2-7x-18=0\\\\ 8x^2-16x+9x-18=0\\\\8x(x-2)+9(x-2)=0\\\\(x-2)(8x+9)=0\ \ \ \Leftrightarrow\ \ \ (x-2=0\ \ \ or\ \ \ 8x+9=0)\\\\.\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x=2\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ x=- \frac{9}{8} [/tex]
