Your first two columns, where you make your guesses, are correct. You simply pick a number at random for the first column and the second column has you subtract off 17. The third column is where you made an error. The term "sum" is the result of adding two or more numbers. For example, the sum of 2 and 3 is 2+3 = 5. So instead of multiplying the columns together, you need to add them. In row 1, you'll have 20+3 = 23 under the "sum" column. In row 2, you'll have 34+17 = 51 in that same column. As for the x term row, then it would be x+(x-17) = 2x-17
Side Note: if you meant to say "product" instead of sum, then your third column would be correct. The product is the result of multiplying two or more numbers together.
