Answer:
★ How to do :-
Here, we are given with a fraction in which we are asked to find the second number in which we get it's product when multiplied as one. We aren't given with the appropriate first number but it's written in thr form of multiplication. If we multiply those numbers, we'll get the value of the first number. After finding the first number, we shift thr obtained value from LHS to RHS. We should always remember that while shifting the numbers, the sign of the appropriate number changes. So, let's solve!!
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➤ Solution :-
{\tt \leadsto 3 \: \bigg( \dfrac{7}{9} \bigg) \times x = 1}⇝3(97)×x=1
First, multiply the numbers on LHS.
{\tt \leadsto \bigg( \dfrac{3}{1} \times \dfrac{7}{9} \bigg) \times x = 1}⇝(13×97)×x=1
First solve the bracket on LHS.
{\tt \leadsto \dfrac{21}{9} \times x = 1}⇝921×x=1
Shift the first fraction from LHS to RHS, changing it's sign.
{\tt \leadsto x = 1 \div \dfrac{21}{9}}⇝x=1÷921
Take the reciprocal of second fraction and multiply both the fractions.
{\tt \leadsto x = \dfrac{1}{1} \times \dfrac{9}{21}}⇝x=11×219
Multiply the fractions now.
{\tt \leadsto x = \dfrac{9}{21}}⇝x=219
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{\red{\underline{\boxed{\bf So, \: the \: other \: number \: is \: \dfrac{9}{21}}}}}So,theothernumberis219
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Verification :-
{\tt \leadsto 3 \: \bigg( \dfrac{7}{9} \bigg) \times x = 1}⇝3(97)×x=1
Substitute the value of x.
{\tt \leadsto 3 \: \bigg( \dfrac{7}{9} \bigg) \times \dfrac{9}{21} = 1}⇝3(97)×219=1
Multiply the numbers on LHS in the bracket.
{\tt \leadsto \bigg( \dfrac{7 \times 3}{9 \times 1} \bigg) \times \dfrac{9}{21} = 1}⇝(9×17×3)×219=1
Multiply the numerators and denominators.
{\tt \leadsto \dfrac{21}{9} \times \dfrac{9}{21} = 1}⇝921×219=1
Multiply the numbers on LHS.
{\tt \leadsto \dfrac{21 \times 9}{9 \times 21} = 1}⇝9×2121×9=1
Multiply the numerators and denominators.
{\tt \leadsto \dfrac{189}{189} = 1}⇝189189=1
Write the fraction in lowest form on LHS.
{\tt \leadsto 1 = 1}⇝1=1
So,
{\sf \leadsto LHS = RHS}⇝LHS=RHS
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Hence verified !!