Your daughter's age now =D
Your age now =A
A = 9D..............................(1)
Next Year:
A + 1 =7[D + 1]................(2), solve for A, D
D = 3 year now
A = 27 years now.
3 + 1 = 4 years -daughter's age next year.
4 x 7 = 28 years - your age next year.