Answer:
1. In 2 years, sum of the ages of Moesha and Shanti = 9g + 7
2. When Moesha's age is twice her present age, Shanti's age will be thrice Moesha's present age.
3. 4 years ago, Moesha was 12 years old and Shanti was 28 years old if g = 5.
Step-by-step explanation:
Moesha's age = 3g + 1
It is given that Shanti's age is twice Moesha's age.
So, Shanti's age = 2(3g + 1)
= 6g + 2
In 2 years time,
Moesha's age = (3g + 1) + 2 = 3g + 3
Shanti's age = (6g + 2) + 2 = 6g + 4
Hence, sum of the ages of Moesha and Shanti = (3g + 3) + (6g + 4)
= 9g + 7
Moesha's age will be twice her present age in 3g + 1 years.
After 3g + 1 years, Shanti's age will be (6g + 2) + (3g + 1) = 9g + 3 years.
= 3(3g + 1)
= thrice Moesha's present age
Hence, when Moesha's age is twice her present age, Shanti's age will be thrice Moesha's present age.
If g = 5,
Moesha's present age = 3g + 1
= 3(5) + 1
= 15 + 1
= 16
Shanti's present age = 6g + 2
= 6(5) + 2
= 30 + 2
= 32
Hence, 4 years ago, Moesha was 16-4 = 12 years old and Shanti was 32-4 = 28 years old.
is only defined for 
, and under this condition we have that 
. But 1.7 > 1, so 
is not a real number.