Which technique is appropriate to factor the quadratic $x^2+5x+6$ in order to simplify rational expressions?

• A. Leave it unfactored
• B. Find two numbers that multiply to $6$ and add to $5$
• C. Use quadratic formula to find irrational roots
• D. Complete the square to rewrite as $(x+2.5{)}^2-0.25$

Answer: (B)