what is the sum of all possible solutions to | x - 4 | ^ 2 + | x - 4 | = 20 ?
"denote | x - 4 | as y : y ^ 2 + y = 20 - - > y = - 5 or y = 4 . discard the first solution since y = | x - 4 | , so it ' s an absolute value and thus can not be negative . y = | x - 4 | = 4 - - > x = 8 or x = - 1 . the sum = 7 . answer : d ."
add(add(const_4, 4), subtract(4, const_4))