Simplify completely: 5√162-3√18-4√98 a) 11√2 b) 8√2 c) 5√2 d) simplified already

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.