Verified Answer :

9x^3 - 8x^2 is the answer. to solve this you must distribute the sign across each parenthetical and then add the like terms (all cubed x variables added to cubed variables and all squared x variables added to squared variable)

Answer: Last option is correct.

Step-by-step explanation:

Since we have given that

\(7x^3-4x^2+2x^3-4x^2\)

We need to find the sum of the polynomials:

So, we first collect the like terms:

\(7x^3-4x^2+2x^3-4x^2\\\\=7x^3+2x^3-4x^2-4x^2\\\\=9x^3-8x^2\)

Hence, the sum of polynomials is \(9x^3-8x^2\)

Therefore, Last option is correct.