Answer: (x+7)(x-2)
We're looking for two numbers that multiply to -14 and also add to 5. Through trial and error, you should find those numbers are 7 and -2.
You can use the FOIL rule to confirm that (x+7)(x-2) expands out to x^2+5x-14
(x+7)(x-2) = x^2-2x+7x-14 = x^2+5x-14