what is common factors in quadratic polynomial x²+8x+15 and x²+3x-10 is:

1. x+3
2. x+5
3. x-5
4. x-3
    

Given polynomials are: x² + 8x + 15 and x² + 3x - 10

Now, their factorization can be done as:

x² + 8x + 15 = x² + 5x + 3x + 15

= x(x + 5) + 3(x + 5)

= (x + 3)(x + 5)  ... (1)

Similarly, x² + 3x - 10 = x² + 5x - 2x - 10

= x(x + 5) - 2(x + 5)

= (x - 2)(x + 5)  ... (2)

From (1) and (2), it is quite clear that (x + 5) is the common factor in both the given polynomials.