Final answer:
To solve the equation x² - 15 = 2x by factoring, rewrite it in standard form and factor the quadratic equation as (x - 5)(x + 3) = 0. The solutions are x = 5 and x = -3.
Step-by-step explanation:
To solve the equation x² - 15 = 2x by factoring, we first rewrite it in standard form:
x² - 2x - 15 = 0.
Now, we can factor the quadratic equation as (x - 5)(x + 3) = 0.
Setting each factor equal to zero, we have x - 5 = 0 or x + 3 = 0.
Solving for x, we find x = 5 or x = -3.
Therefore, the correct answer is A) x² - 2x - 15 = 0.