Hi again! I'm being a serial pest, I know it- I'm sorry! If you can only help with one or two of these I would be grateful! thanks so much!

I need help with this inequality its a quadratic division- I' not sure how to approach it? Do I factor or use the Q formula?

x^2- 7x +10/ x^2 + 8x + 15 is < or = to 0

Have I solved this correctly?

log x + log(x -15)=2

log x =2- log(x -15)

x =2-x -15

x+x=2-15

2x= -13

x=-13/2

Ive done this wrong haven't I?

And the Trig:

sin2x + sin5x=0

sin2x= -sin5x

2x=-5x???

Not doing this one right either!

And finally:

x^3 + x^2 + x +1 find all zeros real and complex - I just need to know how to tackle said problem, not the answer.

Thank you for any help at all!