For this case we have the following system of equations:

Equating the values of y we have:

From here, we can clear the value of x.
We have then:

Then, we look for the value of y.
For this, we substitute x in any of the equations:
Answer:
The ordered pair solution of the system of equations, is given by:
we know that
p^2 is the the frequency of hba homozygote
we are given
frequency of hba homozygotes is 0.1
so,
p^2 =frequency of hba homozygotes
we can plug values
and we get
..............Answer
Using the distributive property an equivalent expression would be 9z-54