Answer :
We start with the expression
[tex]$$
\left(x^7+12x^6+7x^3\right)-\left(9x^7+8x^6+4x^3\right).
$$[/tex]
First, distribute the negative sign to the second polynomial:
[tex]$$
x^7 + 12x^6 + 7x^3 - 9x^7 - 8x^6 - 4x^3.
$$[/tex]
Next, combine like terms:
1. For [tex]$x^7$[/tex]:
[tex]$$
x^7 - 9x^7 = -8x^7.
$$[/tex]
2. For [tex]$x^6$[/tex]:
[tex]$$
12x^6 - 8x^6 = 4x^6.
$$[/tex]
3. For [tex]$x^3$[/tex]:
[tex]$$
7x^3 - 4x^3 = 3x^3.
$$[/tex]
So, the resulting polynomial is
[tex]$$
-8x^7 + 4x^6 + 3x^3.
$$[/tex]
Thus, the correct answer is option D.
[tex]$$
\left(x^7+12x^6+7x^3\right)-\left(9x^7+8x^6+4x^3\right).
$$[/tex]
First, distribute the negative sign to the second polynomial:
[tex]$$
x^7 + 12x^6 + 7x^3 - 9x^7 - 8x^6 - 4x^3.
$$[/tex]
Next, combine like terms:
1. For [tex]$x^7$[/tex]:
[tex]$$
x^7 - 9x^7 = -8x^7.
$$[/tex]
2. For [tex]$x^6$[/tex]:
[tex]$$
12x^6 - 8x^6 = 4x^6.
$$[/tex]
3. For [tex]$x^3$[/tex]:
[tex]$$
7x^3 - 4x^3 = 3x^3.
$$[/tex]
So, the resulting polynomial is
[tex]$$
-8x^7 + 4x^6 + 3x^3.
$$[/tex]
Thus, the correct answer is option D.