x² - 20x + 100
Once again, I'll just go through all of the answer choices :)
a) (x - 5)(x - 4)
Simplify.
x² - 4x - 5x + 20
Add like terms.
x² - 9x + 20
So, A is incorrect.
b) (x - 10)(x - 10)
Simplify.
x² - 10x - 10x + 100
Add like terms.
x² - 20x + 100
So, B is correct.
c) (x + 10)²
(x + 10)(x + 10)
Simplify.
x² + 10x + 10x + 100
Add like terms.
x² + 20x + 100
So, C is incorrect.
d) (x + 10)(x - 10)
Simplify.
x² - 10x + 10x - 100
Add like terms.
x² - 100
So, D is incorrect.
Therefore, B is correct.
~Hope I helped!~
