Answer:
The answer is a:b is 9:2.
Explanation:
In order to determine the answer, we have to know about ratio.
A ratio is a fraction of two measures. If a fraction is a/b, we can express this fraction as a:b, so:
a/b=a:b
In this case, we have an expression that shows the variable "a" and "b". So we have to modify this expression to get the correct form of a ratio.

Then, we express the fraction as:
a:b=9:2
Finally, the ratio for a:b is 9:2.