CREATE TABLE table_9696 ("Scorer" TEXT, "Club" TEXT, "League goals" TEXT, "FA Cup goals" FLOAT, "League Cup goals" FLOAT, "Total" FLOAT)

Which FA Cup goals have a League goals of 18, and a Club of sheffield united?
SELECT MAX("FA Cup goals") FROM table_9696 WHERE "League goals" = '18' AND "Club" = 'sheffield united'
SELECT MAX("FA Cup goals") FROM "table_9696" WHERE "Club" = 'sheffield united' AND "League goals" = '18'