The answer is A) 2x + 7.
When you are doing synthetic division, you always pull down the first number to the end area like this.
1 ║ 2 9 7
2
After that you multiply it's result by the number in the front. Then you add it's result to the second number. 2 * -1 = -2. So we add -2 to 9 and pull that down.
1 ║ 2 9 7
2 7
Now we repeat that process and multiply the 7 by -1. The result is -7, and we add that to 7.
1 ║ 2 9 7
2 7 0
If the end result is 0, that means the division went in evenly, with no remainders. We can now add an decreasing number of x's to all of the numbers that came through other than 0.
2x + 7
