Sam + Linda = 14 years.
(Linda+4) + Linda = 14. <<<---=== Notice how nice I formatted it !
I did it for your better understanding !
2*Linda + 4 = 14.
2*Linda = 14 - 4 = 10.
Linda = 10/2 = 5.
ANSWER. Linda is 5 years old. Sam is 5+4 = 9 years old.
CHECK. 5 + 9 = 14 years. ! Correct !