add the following

(-8x^2-2x+4)+(x^2-9x+7)

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

-8x^2+x^2 -2.4x+(-9x) +4+7=
-7x^2 -2.4x-9x +11=

-7x^2 -11.4x +11

(-8x^2-2x+4)+(x^2-9x+7)

to add, we just combine the numerical coefficients (or the numbers before the variable) of the same variables (meaning same letters and same exponents).
thus,
(-8x^2 - 2x + 4 ) + ( x^2 - 9x + 7 )
-7x^2 - 11x + 11

hope this helps~ :)

To add the two polynomials (-8x^2-2x+4) and (x^2-9x+7), you need to combine like terms. Like terms have the same variables raised to the same exponents.

First, let's add the terms with x^2:
-8x^2 + x^2 = -7x^2

Next, let's add the terms with x:
-2x - 9x = -11x

Finally, let's add the constant terms:
4 + 7 = 11

Therefore, the sum of the two polynomials (-8x^2-2x+4)+(x^2-9x+7) is:

-7x^2 - 11x + 11