Answer: They are both correct :)
Explanation:
They are both correct because 7x + (-3) is the same thing as 7x - 3 if you simplify it.
When you simplify it, you change the expression to:
7x + 1 (-3)
So now you have to distribute the 1 which gives you:
7x - 3
..since positive x negative is negative.
Hope that helped!