Given:
To find:
The value of "x" and "y".
Solution:
Let's solve "x" first.
Given is a supplementary angle so it should add up to 180°
![x=180-123](https://img.qammunity.org/2023/formulas/mathematics/high-school/79t1jbhrgdrs1x12wa48esfpaaq9k64xm9.png)
![\large\boxed{x=57°}](https://img.qammunity.org/2023/formulas/mathematics/high-school/p1cyj1ie6qrv2breud3fixg55qifwxwszc.png)
Now, we can solve "y"
Given is an isosceles triangle so the opposite sides will be equal.
![57+57](https://img.qammunity.org/2023/formulas/mathematics/high-school/53j3n2jm0h67w3srk1zz4tq6ev0k5drenl.png)
![114°](https://img.qammunity.org/2023/formulas/mathematics/high-school/3gd7aucme6ngwod7m6uskjor6wggdwi9mu.png)
Angle sum of triangle is 180° so, it should add up to 180°
![y=180-114](https://img.qammunity.org/2023/formulas/mathematics/high-school/v9fpee6clv9tu83z1y3x4ktock51dgg346.png)
![\large\boxed{y=66°}](https://img.qammunity.org/2023/formulas/mathematics/high-school/id763jhkxbd0q3lse8yzw9f6haskq1neoy.png)
Therefore, the correct answer is option C