The Total solution for NCERT class 6-12
Let’s consider a tobe the first term and r to be the common ratio of the G.P.
Given, a =–3
And we know that,
an = arn–1
So, a4 = ar3 =(–3) r3
a2 = a r1 = (–3) r
Then from thequestion, we have
(–3) r3 =[(–3) r]2
⇒ –3r3 =9 r2
⇒ r =–3
a7 = a r 7–1 = a r6 =(–3) (–3)6 = – (3)7 = –2187
Therefore, the seventhterm of the G.P. is –2187.