Problem: what is the smallest positive perfect square that is divisible by 9 , 21 , and 49 ?
Rationale: "the number needs to be divisible by 3 ^ 2 , 3 * 7 , and 7 ^ 2 . the smallest such perfect square is 3 ^ 2 * 7 ^ 2 = 441 the answer is c ."
annotated_formula: add(multiply(multiply(multiply(9, power(const_3, const_2)), 21), const_2), multiply(21, 49))