Question

In the group {1,3,7,9} under *10,(3*10 7^-1)-1 =

Answer 1

5×-1=-5

Step-by-step explanation:

The answer is -5

Answer 2

Answer:

$\bf\,(3\,*_{10}\,7^{-1})^{-1}=9$

Step-by-step explanation:

In the group {1,3,7,9}

$3\,*_{10}\,7=1$

$\textbf{Inverse of 3 is 7}$

$\implies\,3^{-1}=7$

$\text{Now,}$

$(3\,*_{10}\,7^{-1})^{-1}$

$\text{Using,the property}$

$\boxed{\bf\,(a*b)^{-1}=b^{-1}*a^{-1}}$

$=(7^{-1})^{-1}\,*_{10}\,3^{-1}$

$\text{Using,the property}$

$\boxed{\bf\,(a^{-1})^{-1}=a}$

$=7\,*_{10}\,3^{-1}$

$=7\,*_{10}\,7$

$=9$

$\implies\,\boxed{(3\,*_{10}\,7^{-1})^{-1}=9}$