Answer
C. $ab = C$ and $a+b=B$
Work Step by Step
If $x^2+Bx+C=(x+a)(x+b),$
then the answer is C:
$ab = C$ and $a+b=B$
To prove this, we can use the FOIL method for the terms in the problem:
$(x+a)(x+b)=$
$x^2+xb+xa+ab$
Therefore, seeing that ab is the last term, we know it corresponds with C, and seeing that the sum of xb and xa is the second term, then $a+b$ corresponds with the B term.
