ANSWER
a) Use the homogeneous property of the binomial expansion to find the missing exponent
b) Use the binomial theorem to find the coefficient
Step-by-step explanation
The given binomial expansion is:

When we compare this to

We have

Therefore the of each term in the expansion must be 12.



Since the coefficient of x and y are unity, we use the formula

to find the coefficient.
Where n=12 and r=5(the exponent of the y-term).
Therefore the coefficient is



When we simplify further we get:
