Problem: if a - b = 3 and a ( power 2 ) + b ( power 2 ) = 23 , find the value of ab .
Rationale: "2 ab = ( a ( power 2 ) + b ( power 2 ) - ( a - b ) ( power 2 ) = 23 - 9 = 14 ab = 7 . answer is c ."
annotated_formula: divide(subtract(23, power(3, 2)), 2)