1990, the mother's age is seven times that of her daughter, 1998 (that is, the age of both mother and daughter has increased by eight years), and the mother's age is three times that of her daughter. At this time, the mother's age is equal to the original age of three eights plus three daughters (as shown in the schematic diagram). After subtracting two eights, the mother's original age should be three times that of her daughter, so two eights are 6544.

1998- 1990=8

Daughter's original age: 8×(3- 1)÷(7-3)=4? (years old)

Mother's original age: 4×7=28 (years)

Mother's birth year: 1990-28= 1962.