Hello! I would love to help!
Let's start with this part of the equation: "the sum of a number and seven"
Alright. We know that x represents an unknown number. Do you see a part of the equation that could translate to "an unknown number?"
I see "a number." So let's fill X in for "a number.
Alright. So now we have "the sum of x and 7."
Next, let's remember that sum means adding. So we just need to 7 to x
X+7
So, now instead of "the sum of a number and 7" we have x+7.
Alright. Now we just have to do the "twice." When it is asking for "twice", it is asking us to multiply our answer by two. But we need to multiply both x and 7. The best way to do that is to put our "x+7" in parenthesis and put a two outside.
2(x+7)
That's your answer! 2(x+7)
Hope this helped! Comment if you have any questions!