Question

- Multiply.
(9w-2u)(9w+2u)
Simplify your answers.​

Answer 1

81w² - 4u²

Explanation:

To multiply two binomials together, we would normally use the FOIL method.

First

Outer

Inner

Last

But if we look carefully, we can see that there is a much easier way to multiply the two binomials. Remember:

(a + b)(a - b) = a² - b²

(9w - 2u)(9w + 2u) = (9w)² - (2u)² = 81w² - 4u²

I hope you find my answer and explanation to be helpful. Happy studying.

Answer 2

Answer: 81w^2 - 4u^2

Explanation:

(9w - 2u)(9w + 2u) Apply the distributive property twice than combine them.

9w( 9w + 2u) = 81w^2 + 18wu

-2u(9w + 2u) = -18wu - 4u^2

81w^2 + 18wu - 18wu - 4u^2 Combine like terms

81w^2 - 4u^2