if a ( a - 7 ) = 8 and b ( b - 7 ) = 8 , where a ≠ b , then a + b =
"i . e . if a = - 1 then b = 8 or if a = 8 then b = - 1 but in each case a + b = - 1 + 8 = 7 answer : option d"
subtract(subtract(subtract(subtract(add(add(7, 8), subtract(7, 8)), const_1), const_1), const_1), const_1)