Answer:
(x-3)
Step-by-step explanation: First look what which two numbers would multiply to -15 and add to 2. In this case, it's 5 and -3 because 5x-3=15 and 5+(-3)=2.
So the other factor is (x-3)
To check your work, simply multiply
(x+5)(x-3) = x2 + 2x - 15
