The Zero Product Property states that if the product of two factors is equal to zero, then at least one of the factors must be equal to zero.
In your quadratic equation \((5x + 1)(x - 8) = 0\):
- For the left side to equal zero, at least one of the factors \((5x + 1)\) or \((x - 8)\) must be equal to zero.
Therefore, the statement that must be true is: "At least one of the factors, (5x + 1) or (x - 8) must equal 0 for the left side of the equation to equal 0."