need help for how to get rid of the squares without turning it into an expression with two answers.

"Tom is 3 years younger than his brother Phil. how old are they when the sum of the squares of their age is 117. Let x be feels age and then write an expression for Tom's age as it relates to Phil's age. use these expressions to solve for their ages algebraically."
x^2 + (x-3)^2 =√117​