1. The problem asks to explain what each part of the equation represents in the situation where Marta was 10 when her little brother was born, and the equation relates their ages. 2. The variables are defined as: - $X$ = brother's age - $Y$ = Marta's age 3. The equation representing the situation is: $$Y = X + 10$$ 4. Explanation of each part: - $X$ represents the brother's current age. - The number 10 represents the age difference between Marta and her brother, since Marta was 10 years old when he was born. - $Y$ represents Marta's current age, which is always 10 years more than her brother's age. Thus, for any brother's age $X$, Marta's age $Y$ is $X + 10$.