Question

Hey:) can you please help me posted picture of question

Answer 1

Correct answer is option C.

The solution using FOIL method is shown below:

$( x^{8}- x^{4})( x^{5}-9) \\ \\ = x^{8}( x^{5}-9)-x^{4}( x^{5}-9) \\ \\ = x^{13}-9 x^{8}- x^{9}+9 x^{4}$

Answer 2

Answer:
x¹³ - x⁹ - 9x⁸ + 9x⁴

Explanation:
Before we begin, remember the following:
xᵃ * xᵇ = xᵃ⁺ᵇ

Now, for the given:
To answer the question, we will simply multiply each term from the first bracket by each term from the second bracket and then combine like terms to get the final expression.

This can be done as follows:
(x⁸ - x⁴)(x⁵ - 9)
x⁸(x⁵) + x⁸(-9) - x⁴(x⁵) - x⁴(-9)
x¹³ - 9x⁸ - x⁹ + 9x⁴

Rearrange in order of decreasing powers, we will end up with:
x¹³ - x⁹ - 9x⁸ + 9x⁴

Hope this helps :)