Answer:
![5y+4](https://img.qammunity.org/2021/formulas/mathematics/high-school/bem0q1pqzaj0ukdu1csfu5zsxtvqw6kjwe.png)
Explanation:
What we know:
- 3 ×
is equal to Sara's father's age
-
+ 4 is equal to Sara's brother's age
-
is equal to Sara's age
Sum of their ages = father's age + Sara's age + brother's age
Sum of their ages =
![3y+y+(y+4)](https://img.qammunity.org/2021/formulas/mathematics/high-school/jupio5lnbogr4bbfgk5g3r0qs434qrtdxt.png)
Sum of their ages =
![5y+4](https://img.qammunity.org/2021/formulas/mathematics/high-school/bem0q1pqzaj0ukdu1csfu5zsxtvqw6kjwe.png)
I hope this helps!