Question

Multiply the conjugates.

(x + 2y)(x - 2y)

Please explain your answer with steps so that I can answer these too, thanks in advance.

Answer 1

To multiply the conjugates (x + 2y) and (x - 2y), use the FOIL method. The final answer is x² - 4y².

Step-by-step explanation:

To multiply the conjugates (x + 2y) and (x - 2y), you can use the FOIL method. FOIL stands for First, Outer, Inner, Last.

First, multiply the first terms of each binomial: x * x = x²

Outer, multiply the outer terms of each binomial: x * -2y = -2xy

Inner, multiply the inner terms of each binomial: 2y * x = 2xy

Last, multiply the last terms of each binomial: 2y * -2y = -4y²

Combine the like terms: x² - 2xy + 2xy - 4y²

The middle terms (-2xy + 2xy) cancel each other out, so the final answer is x² - 4y².