Ontario Mathematics Proficiency Practice Test

To solve the equation x² - 9 = 0, we can first recognize that this is a difference of squares. The expression can be factored as (x - 3)(x + 3) = 0. According to the zero product property, if the product of two factors is zero, at least one of the factors must also be zero.

Setting each factor equal to zero gives us the following equations:

1. x - 3 = 0, which simplifies to x = 3.

2. x + 3 = 0, which simplifies to x = -3.

Therefore, the solutions to the original equation are x = 3 and x = -3.

The correct answer reflects this reasoning, showing that the solution set is indeed x = 3 or x = -3.