Question

Qual o valor de: (x + y) · (x - y) =

Answer 1

The answer to this problem is x² - y².

To solve this problem, we can use a factoring technique. In this problem, we see the factored form of the difference of two squares. The difference of two squares, and how they are factored, is:

x² - y² = (x + y)(x - y)

Since we are given the factored form, we must 'unfactor' it. Since the 'unfactored' form is x² - y², the answer to this problem is x² - y².

Answer 2

Use the FOIL method:

FOIL = First, Outside, Inside, Last

(x + y)(x - y)

(x)(x) = x²

(x)(-y) = -xy

(y)(x) = xy

(y)(-y) = -y²

x² - xy + xy - y²

Simplify. Combine like terms

x² (-xy + xy) - y²

x² - y²

x² - y² is your answer

hope this helps