Multiple choice

What is (9x + 10) (9x - 10) in expanded form?

  1. 81x2 + 100

  2. 100x2 - 81

  3. 81x2 - 100

  4. 9x2 - 10

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(9x + 10) (9x - 10) = 81x2 - 90 + 90x - 100 (Using Foil) = 81x2 - 100