P,Q,R can't be 0, because their product is nonzero. Either of S and T could be 0, but the third one only works if S is 0.
Answer:
0.078125.
Step-by-step explanation:
This is a geometric sequence with first term a1 = 20 and common ratio r = 10/20 = 5/10 = 0.5.
nth term = a1 r^(n -1) so here:
9th term = 20(0.5)^(9-1)
= 20(0.5)^8
= 0.078125.
X(^-1)^7=x^6
7(c^1)^2/3=7(c)^2/3
(m^2n^3)^-3=1/m^6n^9
12 2/6 is a mixed number. Though, it can be simplified to 12 1/3