Before we do this problem, let's go over a little algebra terminology.
The number in front of your variable is called your coefficient and notice that the x at the end of the problem does not have a coefficient.
When that happens, when there is no number in front of your variable, you can put a 1 there to fill that position. So -x can be thought of as -1x.
Next let's change all our minus signs to plus negatives.
So the problem reads 3x + 5 + 7x + -3 + -1x + 2.
Now let's simplify this by combining like terms.
We can combine our "x" terms first.
3x + 7x + -1x simplifies to +9x.
Now, 5 + -3 + 2 simplifies to 4.
So our answer is 9x + 4.