daughter = d

s = 7d

s+8 = 3d

Mrs. Sweeny (S) is (=) 7 times as old (7 *) as her daughter (D). Eight years from now (S+8), she will be (=) 3 times (3*) her daughter’s age (D+8).

S = 7*D

S+8 = 3*(D+8)

Simple.

Edit: Two answers so far have forgotten that the daughter will also age eight years. Don’t forget to add 8 to the daughter’s age in the second equation, or else your answer will come out negative!

Daughter Now: x

Mrs Sweeny 8 years from now: 7x + 8

Daughter 8 years from now: x + 8

Mrs. Sweeny 8 years from now is 3 times her daughter’s age 8 years from now.

7x + 8 = 3(x+8)

Got it from there?

x=7y

x+8=3y