Multiply first and last coefficients:
2*(-9) = -18
Find 2 factors which multiply to -18 and add up to 17:
18 and -1
Rewrite quadratic with 17y split up as' 18y - y', Then factor by grouping:
[tex]2y^2 - y + 18y -9 \\ \\ y(2y-1) + 9(2y-1) \\ \\ (2y-1)(y+9)[/tex]
