The 5th, 8th and 11th terms of a G.P. are p,q and r respectively, show that `q^2 = pr`

The 5th, 8th and 11th terms of a G.P. are p, q and x, respectively. Show that q^2=ps .

The 4th, 7th and 10th terms of a GP. are a, b, c respectively. Show that b^2 = ac .

If the 4th, 10th and 16th terms of a G.P. are x, y and z, respectively. Prove that x, y, z are in G.P.

The 5th, 8th, and 11th terms of a GP are p, q and s respectively. Find relation between p,q and s.

If the p^(th) , q^(th) and r^(th) terms of a G.P. are a, b and c, respectively. Prove that a^(q-r) b^(r-p)c^(P-q)=1 .

The p^(th) , q^(th) and r^(th) terms of an A.P. are a, b, c, respectively. Show that (q -r)a+ (r-p )b + (p- q)c= 0

If the 5th and 12th terms of an A.P. are 30 and 65 respectively, what is the sum of the first 20 terms ?

If 6th, 7th, 8th and 9th terms of (x+y)^n are a, b,c and d respectively, then prove that : (b^2-ac)/(c^2-bd)=4/3.a/c .

Sum of the first p, q and r terms of an A.P. are a, b and c, respectively. Prove that a/p(q-r)+b/q(r-p)+c/r(p-q)=0

If 7th and 13th terms of an A.P. be 34 and 64 respectively, then its 18th term is: