Wait, do you mean that y=10 is what you want in slope intercept form? Oh btw I'm not answering this just for the points. I'll actually answer the question
Can you attach a pic of the shape please?
We have,

Introduce variable
such that 
The sum
is therefore 
So,
(sadia's age)
(father's age)
Hope this helps :)
Answer:
C)
Step-by-step explanation: