Rajasthan BoardEnglish MediumSTD 9MATHSNumber systems1 Mark
Question
If $\frac{3^{5\text{x}}\times81^2\times6561}{3^{2\text{x}}}$ then x =
✓
Answer
$-3$ Solution: We have to find the value of x provided $\frac{3^{5\text{x}}\times81^2\times6561}{3^{2\text{x}}}=3^7$ So, $\frac{3^{5\text{x}}\times81^2\times6561}{3^{2\text{x}}}=3^7$ By using law of rational exponents we get $3^{5\text{x}+8+8-2\text{x}}=3^7$ By equating exponents we get $5\text{x}+88-2\text{x}=7$ $3\text{x}+16=7$ $3\text{x}=7-16$ $3\text{x}=-9$ $\text{x}=\frac{-9}{3}$ $\text{x}=-3$ Hence the correct choice is b.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.