* (x - 3)/(9^x - √3) <= 0 ≡
≡ (x != 1/4) & ((x = 3) oppure ((x - 3)*(9^x - √3) < 0)) ≡
≡ (x != 1/4) & (x = 3) oppure ((x < 3) & (9^x > √3) oppure (x > 3) & (9^x < √3)) & (x != 1/4) ≡
≡ (x = 3) oppure ((x < 3) & (x > 1/4) oppure (x > 3) & (x < 1/4)) & (x != 1/4) ≡
≡ (x = 3) oppure ((1/4 < x < 3) oppure (insieme vuoto)) & (x != 1/4) ≡
≡ (x = 3) oppure (1/4 < x < 3) & (x != 1/4) ≡
≡ 1/4 < x <= 3