The question asks you to add 9 to an unknown number...since you donʻt know that number you use the letter x. The question asks you to multiply 6 by the SUM of 9 + a number (x) so you have to put 9+x in parentheses, because acording to the order of operations you do parentheses first. After you put it all together you get the answer of: 6(9+x)
