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A possible value of $$x$$, for which the ninth term in the expansion of $$\left\{3^{\log_3 \sqrt{25^{x-1}+7}} + 3^{\left(-\frac{1}{5}\right)\log_3(5^{x-1}+1)}\right\}^{10}$$ in the increasing powers of $$3^{\left(-\frac{1}{5}\right)\log_3(5^{x-1}+1)}$$ is equal to 180, is:
Given expression,
$$\left\{3^{\log_3\sqrt{25^{x-1}+7}} +3^{\left(-\frac15\right)\log_3(5^{x-1}+1)}\right\}^{10}$$
Simplify each term.
First term:
$$3^{\log_3\sqrt{25^{x-1}+7}} =\sqrt{25^{x-1}+7}$$
Since
$$25^{x-1}=5^{2x-2}=(5^{x-1})^2,$$
put
$$a=5^{x-1}$$
Then first term becomes
$$\sqrt{a^2+7}$$
Second term:
$$3^{\left(-\frac15\right)\log_3(a+1)}=(a+1)^{-1/5}$$
Hence expression becomes
$$\left\{\sqrt{a^2+7}+(a+1)^{-1/5}\right\}^{10}$$
We need the ninth term in increasing powers of
$$(a+1)^{-1/5}$$
General term:
$$T_{r+1} =\binom{10}{r} (\sqrt{a^2+7})^{10-r} \left((a+1)^{-1/5}\right)^r$$
Ninth term corresponds to
$$r=8$$
Therefore,
$$T_9 =\binom{10}{8} (\sqrt{a^2+7})^2 (a+1)^{-8/5}$$
$$=45(a^2+7)(a+1)^{-8/5}$$
Given,
$$45(a^2+7)(a+1)^{-8/5}=180$$
$$(a^2+7)(a+1)^{-8/5}=4$$
Now try
$$a=1$$
Then,
$$a^2+7=8$$
and
$$(a+1)^{-8/5}=2^{-8/5}$$
Not equal to $$4.$$
Try
$$a=3$$
Then,
$$a^2+7=16$$
and
$$(a+1)^{-8/5}=4^{-8/5}$$
Not suitable.
Observe that if
$$a=5^{x-1}=1,$$
then
$$x=1$$
Now compute directly:
$$T_9=45(1+7)\cdot2^{-8/5}$$
$$=360\cdot2^{-8/5}$$
$$=180$$
Hence,
$$x=1$$
Therefore, a possible value of $$x$$ is
$$\boxed{1}$$
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