Question

what is the sum of the polynomials?
\left(8x^{2}-9y^{2}-4x\
ight)+\left(x^{2}-3y^{2}-7x\
ight)
\bigcirc\\ 7x^{2}-6y^{2}+3x
\bigcirc\\ 9x^{2}-6y^{2}+3x
\bigcirc\\ 9x^{2}-12y^{2}+3x
\bigcirc\\ 9x^{2}-12y^{2}-11x

Explanation:

Step1: Remove parentheses

$8x^2 - 9y^2 - 4x + x^2 - 3y^2 - 7x$

Step2: Combine $x^2$ terms

$8x^2 + x^2 = 9x^2$

Step3: Combine $y^2$ terms

$-9y^2 - 3y^2 = -12y^2$

Step4: Combine $x$ terms

$-4x - 7x = -11x$

Step5: Combine all results

$9x^2 - 12y^2 - 11x$

Answer:

$\boldsymbol{9x^2 - 12y^2 - 11x}$ (corresponding to the last option)