What will come in place of the question mark (?) in the following questions ?
$$(81)^{5}\times(729)^{4}\div(9)^{7} = 9^{?}$$
Let unknown quantity be 'x'.
$$(81)^{5}\times(729)^{4}\div(9)^{7} = 9^{x}$$.
We know that,
$$9^{2}=81, 9^{3}=729$$.
Hence, $$(81)^{5}\times(729)^{4}\div(9)^{7} = 9^{x}$$.
$$9^{10}\times9^{12}\div9^{7}=9^{x}$$.
$$9^{10+12-7}=9^{x}$$.
$$9^{15}=9^{x}$$.
Comparing both sides,
$$x=15$$.
Hence, Option C is correct.
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