Answer :
x - the number
[tex]\frac{3}{7}x=9 \\ x=9 \times \frac{7}{3} \\ x=3 \times 7 \\ x=21[/tex]
3/7 of 21 is 9.
[tex]\frac{3}{7}x=9 \\ x=9 \times \frac{7}{3} \\ x=3 \times 7 \\ x=21[/tex]
3/7 of 21 is 9.