Final answer:
herefore, the factored form of the quadratic expression is (x - 7)(x + 3).
Step-by-step explanation:
To convert the quadratic expression x^2 + 4x - 21 into factored form, we need to find two numbers whose product is equal to the constant term (-21) and whose sum is equal to the coefficient of the middle term (4).
By considering factors of -21, we find that -7 and 3 satisfy these conditions: -7 * 3 = -21 and -7 + 3 = 4.
Therefore, the factored form of the quadratic expression is (x - 7)(x + 3).