Answer:
6
Explanation:
We are given:
Let us use laws of indices to solve.
We know ÷ = Reciprocal of the corresponding number
 Hence, Given can be rewritten as:
We know,by law of indices:
Here 7 acts as a common base. So:
a = 7, b = 10, c = 4; Putting the values:
So the missing exponent is 6.