Question 495330
Try this:
{{{-18a^2 +17a+15}}} FIrst factor a -1.
{{{-(18a^2-17a-15)}}} 
What are the factors of 18?
1*18 = 18
2*9 = 18
3*6 = 18
And what are the factors of 15?
1*15 = 15
3*5 = 15
I would start with 2*9 and 3*15 but you can start with any pairs from both groups and check your solutions..
{{{-(18a^2-17a-15) = -(2a-3)(9a+5)}}}