Question

Алгебра 7 класс (x+y)(x-y)

Answer 1

это формула сокращенного умнажения - ответ: $x^{2}$ - $y^{2}$

Answer 2

To simplify the expression $(x+y)(x-y)$, you can use the distributive property, also known as FOIL (First, Outer, Inner, Last). FOIL helps you multiply two binomials. Here's how it works:

$(x+y)(x-y) = x \cdot x + x \cdot (-y) + y \cdot x + y \cdot (-y)$

Now, simplify each term:

$x \cdot x = x^2$ (since $x \cdot x = x^2$)

$x \cdot (-y) = -xy$ (when multiplying a positive number by a negative number, the result is negative)

$y \cdot x = xy$ (since multiplication is commutative, $y \cdot x$ is the same as $x \cdot y$)

$y \cdot (-y) = -y^2$ (when multiplying a positive number by a negative number, the result is negative)

Now put everything together:

$(x+y)(x-y) = x^2 - xy + xy - y^2$

The middle terms, $xy$ and $-xy$, cancel each other out:

$(x+y)(x-y) = x^2 - y^2$

So, the simplified expression is $x^2 - y^2$.