Question

2. Efectuați folosind formula produsului sumei cu diferența:
a) (x + 7)(x - 7);
b) (3 - x)(3+x);
c) (2x + 1)(2x - 1);
d) (3x + 2)(3x - 2);
e) (3a - b)(3a + b);
f) (2x + 3y)(2x - 3y);
g) (x + 5y)(x - 5y);
h) (3x - 4)(3x + 4)
i) (a - 6)(a + 6);
j) (3x + 7)(3x - 7);
k) (5x + 4)(5x - 4);
1) (7x+3)(78-3).

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Answer 1

Răspuns:

a) (x + 7)(x - 7) = x² - 7² = x² - 49  

b) (3 - x)(3+x) = x² - 3² = x² - 9  

c) (2x + 1)(2x - 1) = (2x)² - 1² = 4x² - 1  

d) (3x + 2)(3x - 2) = (3x)² - 2² = 9x² - 4  

e) (3a - b)(3a + b) = (3a)² - b² = 9a² - b²

f) (2x + 3y)(2x - 3y) = (2x)² - (3y)² = 4x² - 9y²

g) (x + 5y)(x - 5y) = x² - (5y)² = x² - 25y²

h) (3x - 4)(3x + 4) = (3x)² - 4² = 9x² - 16  

i) (a - 6)(a + 6) = a² - 6² = a² - 36

j) (3x + 7)(3x - 7) = (3x)² - 7² = 9x² - 49

k) (5x + 4)(5x - 4) = (5x)² - 4² = 25x² - 16

1) (7x+3)(7x-3) = (7x)² - 3² = 49x² - 9

(a - b)(a + b) = a² - b²