Answer:
a:b = 3/7
Explanation:
we need to find the ratio a:b which is the same as a/b.
7a=3b
Devide left and right of the = sign by b gives
7a/b = 3 * b/b
7a/b = 3 * 1
7a/b = 3
Multiply left and right of the = sign by 1/7 gives
1/7 * 7a/b = 1/7 * 3
7/7 * a/b = 3/7
1 * a/b = 3/7
a/b = 3/7
Since a/b is the same as a:b, we now have the answer.
a:b = 3/7