Express the fraction 1/15 as a decimal

How do i do this activity, is appreciated

Three numbers x, y, and z are in the ratio 2: 7: 8. if 12 is subtracted from y, then three numbers form a geometric sequence (in the order x, y–12, z). find x, y, and z. there are 2 sets.

(x-5)1/2+5=2 what is possible solution of this equation