what numbers multiply to -210 , but also add up to -1 ?

What numbers multiply to  -210  but add to  -1?

 

Since the product is a negative, one number must be positive and the other must be negative.

Since the sum is -1, the two numbers (in absolute value) must be consecutive numbers.

 

Find the square root of  210   --->  it is 14.49...

So the two numbers (in absolute value) should be 14 and 15.  

Since their sum is a negative, the numbers are  14  and  -15.