Query about Question 19 from "Algebra Foundation Quiz #1" [1772]

https://prepswift.gregmat.com/quizzes/quiz/algebra-foundation-quiz-1-hadr (Question 19)


I got the formula (x/100 = 4x^2) for this correct, but I’m so confused about how to actually solve the resulting formula algebraically…. My instinct was to multiply both sides by 100 to get x = 400x^2. then set that equal to 0 so …

400x^2 - x = 0
…. did everyone then do the quadratic formula to get x =0.0025? is that the quickest way to roll?

Or divide by x on both sides. Note that there is no need to watch out for 0 since the question explicitly says that the number is not 0.