Question

perform the indicated operation (7x4 + 11x3 – x2 – 8x + 6) – (-12x4 + 9x2 – 15)

Answer 1

Combine like terms.
Like terms have the same variable raised to the same power.
7x^4 + 12x^4 = 19x^4
11x^3
-x^2 - 9x^2 = -10x^2
-8x
6 + 15 = 21
19x^4 + 11x^3 -10x^2 -8x + 21

Answer 2

Answer:

$19x^4 + 11x^3 - 10x^2 - 8x + 21$

Step-by-step explanation:

We have the expression:

$(7x^4 + 11x^3 - x^2 - 8x + 6) - (-12x^4 + 9x^2 - 15)$

The first step is to apply the indicated subtraction, respecting the law of signs.

$7x^4 + 11x^3 - x^2 - 8x + 6 +12x^4 - 9x^2 + 15$

Now we put together like terms (those that have the same variable with the same exponent).

adding $7x^4$ and $12x^4$

$19x^4 + 11x^3 - x^2 - 8x + 6 - 9x^2 + 15$

adding $-x^2$ and $-9x^2$

$19x^4 + 11x^3 - 10x^2 - 8x + 6 + 15$

and adding $+6$ and $+15$

$19x^4 + 11x^3 - 10x^2 - 8x + 21$

the answer is:

$19x^4 + 11x^3 - 10x^2 - 8x + 21$