Let [tex]x[/tex] be the age of Sam and [tex]y[/tex] be the age of Tomas. The sum of the ages of Sam and Tomas is 27 years. In symbols:
[tex]x + y = 27[/tex]
Seven years ago, Tomas's age was [tex]y-7[/tex]. Meanwhile,
seven years ago, Sam's age was [tex]x-7[/tex]. Therefore, the statement
"Seven years ago,Tomas was three years more than one-fourth as old as Sam" written in symbols is
[tex]y-7 = \frac{1}{4} (x-7) + 3[/tex]