h(x)= 2x^{2}-5x-4

The back of the books tells me that the answer is (5 - the square root of 57 over 4. ,0) , (5 + the square root of 57 over 4. ,0) but I can't figure out how that was gotten. In the section above, we were working on completing the square so am I supposed to do the same and then find the intercepts by replacing y with 0?

Thanks in advance