How do i solve x/2+1/3=x/3+1/2

Which simplifys to a+ b? a-(1-b)+1 -(1-a)-b+1 (a--1) -1)+1

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?

How many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.) how many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.)