Answer:
For this expression:
a=15 , b=7 and c=4
Explanation:
We are asked to find the value of a,b and c by representing the given expression:
in the form of:

where a is the base and b is the numerator of the exponent and c is the denominator of the exponent.
We know that the expression of the type:
is also written as:

Hence, we get our expression as:
![\sqrt[4]{15^7}=(15^7)^{(1)/(4)}\\ \\\\i.e.\\\\\\\sqrt[4]{15^7}=(15)^{(7)/(4)}](https://img.qammunity.org/2020/formulas/mathematics/middle-school/s1tf3wkprjh6rlv623xu3m21v0xydoja0f.png)
Hence, we have:
a=15, b=7 and c=4