Answer: A. {5, -5 }
Step-by-step explanation: I believe this is the answer because the equation split up is 3 * x² - 75 = 0 In this equation (since it equals 0) you need to find how 3x² equals 75. if you do 25, the answer of the equation will be 1875 not 75. if you do 5, it equals 75 because you have to do exponents first so 5 times it self equals 25, then 25 * 3 equals 75, Finally you get 75 - 75 = 0. Also, if your worrying is the answer A. {5,-5} or B.{5} the answer is A. because -5 times it self is also 25. Please mark Brainliest.