To find the other factor of the polynomial x² + 20 when one of the factors is x + 5, we can use polynomial long division or factorization methods. However, in this case, we can first rewrite the expression.
The polynomial x² + 20 can be expressed as:
x² + 20 = x² + 5x + 5x + 20
This can be grouped as:
= x(x + 5) + 4(x + 5)
This leads to:
= (x + 5)(x + 4)
From this factorization, we see that if one of the factors is x + 5, then the other factor is x + 4. Therefore, the other factor of the polynomial x² + 20 is:
x + 4