Question

give me the answer of ques- 17 18



pls don't give irrelevant answers pls​

Answer 1

$\large \underline{ \underline{ \rm \: question \: 17}}$

Given equation :

$\\ \large \tt \leadsto { \left( \dfrac{3}{8} \right) }^{ - 5} \times { \left( \dfrac{16}{21} \right) }^{ - 5} = { \left( \dfrac{2}{7} \right) }^{ x}$

take - 5 as common for L.H.S

$\\ \large \tt \implies{ \left( \dfrac{3}{8} \times \dfrac{16}{21} \right) }^{ - 5} = { \left( \dfrac{2}{7} \right) }^{ x} \\ \\ \\ \tt \implies{ \left( \dfrac{ \cancel3}{8} \times \dfrac{16}{ \cancel{21} \: \: 7} \right) }^{ - 5} = { \left( \dfrac{2}{7} \right) }^{ x} \\ \\ \\ \tt \implies{ \left( \dfrac{1}{ \cancel8} \times \dfrac{ \cancel{16} \: \: 2}{7} \right) }^{ - 5} = { \left( \dfrac{2}{7} \right) }^{ x} \\ \\ \\ \tt \implies{ \left( \dfrac{2}{7} \right) }^{ - 5} = { \left( \dfrac{2}{7} \right) }^{ x}$

Since,

• Bases are same, powers can be equated

$\\ \large\tt \implies{ \left( \dfrac{2}{7} \right) }^{ - 5} = { \left( \dfrac{2}{7} \right) }^{ x} \\ \\ \\ \large \sf \boxed{ \underline{ \sf \therefore \: \: x = - 5}}$

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$\large \underline{ \underline{ \rm \: question \: 18}}$

• a ) 0.000127

$\large \tt \mapsto \: \dfrac{127}{1000000}$

• b) 0.05

$\large \tt \mapsto \: \dfrac{5}{100} = \frac{1}{20}$