2)^10; b) (5x - 1)^6 = 729; c) 9^x : 3^x = 3; d) 3^x + 3^x + 3 = 756

Tìm x, biết:
a) (1/16)^x = (1/2)^10
b) (5x - 1)^6 = 729
c) 9^x : 3^x = 3
d) 3^x + 3^x + 3 = 756