Could you make this easier to read, perhaps by ensuring that you have copied the original problem exactly?
What I read, which may or may not be correct, is:
15x^2 - 35x + 24.
I graphed this on my calculator and found that the graph, a parabola opening up, never touches or crosses the x-axis. Thus, the given equation has no real roots.
If you were to find the discriminant, b^2 - 4ac, you'd find that it's negative, which is another strong clue that there are no real roots.