Which expression is equivalent to (x^2 -8) - (-2x^2+4)?

D) 3x^2 - 12

Step-by-step explanation:

Using PEMDAS;

There is no need to evaluate the part of the equation (x^2 - 8) because is no need to, as it is already in its simplest form.

We must evaluate the part of the equation continuing with, "- (-2x^2+4)," as it is not in its simplest form.

Evaluating "- (-2x^2+4)":

Step 1: Distributing the negative

Once distributing the negative symbol amongst the values within the parenthesis according to PEMDAS, we get "2x^2 - 4" as the product.

Step 2: Consider the rest of the equation to evaluate

Since the part of the equation is still in play here as it is a part of the original equation to be solved, we must evaluate it as a whole to get the final answer.

Thus,

x^2 -8 + 2x^2 - 4 = ___

*we can remove the parenthesis as it has no purpose, since it makes no difference.

Evaluating for the answer, we get,

x^2+2x^2 + (-8 - 4) = 3x^2 - 12

Hence, the answer is D) 3x^2 - 12.