ok so what is sqrt(7)x = 21? well you just 1/sqrt(7) * sqrt(7)x = 1/sqrt(7) * 21 so x = sqrt(7)^2 * 3 / sqrt(7) = sqrt(7) * 3 but you didn't compute the inve

ok so what is sqrt(7)x = 21? well you just 1/sqrt(7) * sqrt(7)x = 1/sqrt(7) * 21 so x = sqrt(7)^2 * 3 / sqrt(7) = sqrt(7) * 3 but you didn't compute the inverse did you, and neither did i. you factored 21 and used the cancellation law (ax = ay => x = y)