Question

1) (x + y)(x - y); 3) (k − 2)(k + 2); 5)(4+b)(4-b);

Answer 1

$(x + y)(x - y) \\ (a + b)(a - b) = a {}^{2} - b {}^{2} \\ x {}^{2} - y {}^{2}$

$(k - 2)(k + 2) \\ k {}^{2} - 4$

$(4 + b)(4 - b) \\ 16 - b {}^{2}$

Answer 2

Ответ:

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

3) (k - 2)(k + 2) = k^2 - 2^2 = k^2 - 4

5) (4 + b)(4 - b) = 4^2 - b^2 = 16 - b^2

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Объяснение:

Раскрыли скобки по ФСУ

(a + b)(a - b) = a^2 - b^2

Answer 3

It looks like you've provided three expressions, and it seems you want to expand them. To expand these expressions, you can use the distributive property (FOIL method for binomials), which states that for any two binomials (A + B) and (C + D):

(A + B)(C + D) = AC + AD + BC + BD

Let's apply this property to the expressions you've given:

1. (x + y)(x - y): = xx + x(-y) + yx + y(-y) = x^2 - xy + xy - y^2 = x^2 - y^2

2. (k - 2)(k + 2): = kk + k2 - 2k - 22 = k^2 + 2k - 2k - 4 = k^2 - 4

3. (4 + b)(4 - b): = 44 + 4(-b) + b4 + b(-b) = 16 - 4b + 4b - b^2 = 16 - b^2

So, the expanded forms of the given expressions are:

1. x^2 - y^2
2. k^2 - 4
3. 16 - b^2