a) 225:15 + 3.(2x + 1) = 270b) 19.(2 + 3 + 4 – 5 + 6 – 7)² – 9.(7x – 2) = 0;c) 3.(2x + 1)³ = 81;d) (x + 1)⁵ = 243;e) 2.11^x = (3² + 2)³ : (5³ – 2⁵:2³).22;g) 7^x + 7^{x + 1} + 7^{x + 2} = 3.19.343.