Answer:
-2x^2+6x+6
Explanation:
First, you need to understand you can combine terms if they have the same degree variable. Or in other words if there is a number with x^2 next to it you can add or subtract any other number with an x^2 next to it. But you cannot if it has any other variable, so if it is brought to a different power oe it's a different letter or symbol.
Next, when you have a minus sign outside of a set of prenthesis like this you actually distriite it, or in other words it changes the signs of everything inside the parenthesis. So -(4x^2-2x-3) will also equal -4x^2+2x+3.
So now this leaves us with 2x^2+4x+3-4x^2+2x+3. We can rearrange it to make thing easier, basically getting everything witht he same variable together. so 2x^2-4x^2+4x+2x+3+3 and from there we can easily combine everything So for instance you take 2x^2-4x^2 and perform the subtraction to get -2x^2 and do that with the rest.