How to answer this on descending powers of x please help pretty please

Question

asked Mar 25, 2020 183k views

1 Answer

Jeff Widmer · Answer 1 · 2020-03-29T13:12:04+0000

Answer: 25x² - 64

Explanation:

(5x + 8)(5x - 8)

= 5x(5x - 8) + 8(5x - 8)

= 25x² - 40x + 40x - 64

= 25x² + 0x - 64

=
$\large\boxed{25x^2-64}$

NOTE: descending powers means the biggest exponent goes first, then the next biggest exponent, etc.

For example: x⁴ then x³ then x² then x then the number (which is actually x⁰)