Question

Am nevoie pentru astazi

Answer 1

Se aplică formula (a-b)(a+b) = a² - b².

a) (√3x + √5)(√3x - √5) = (√3x)² - √5² = √3² · x² - 5 = 3x² - 5

b) (2x - √3)(2x + √3) = (2x)² - √3² = 4x² - 3

c) (x-√7)( x+√7) = x² - √7² = x² - 7

d) (√2x - 3√3)(√2x + 3√3) = (√2x)² - (3√3)² = 2x² - 3²·3 = 2x² - 27

e) (1/3 x - 1/2)(1/3 x + 1/2) = (1/3 x)² - (1/2)² = 1/9 x² - 1/4

f) (2/3 a - 1)(2/3 a + 1) = (2/3 a)² - 1² = 4/9 a² - 1

g) (7/5 x + 3/4 y)(7/5 x - 3/4 y) = (7/5 x)² - (3/4 y)² = 49/25 x² - 9/16 y²

h) (1/5 x + 2/3 y)(1/5 x - 2/3 y) = (1/5 x)² - (2/3 y)² = 1/25 x² - 4/9 y²

i) (3√2 x + 1/7)(3√2 x - 1/7) = (3√2 x)² - (1/7)² = 3² · √2² · x² - 1/49 = 18x² - 1/49

j) (√2 x - 1/√2 y)(√2 x + 1/√2 y) = (√2 x)² - (1/√2 y)² = √2² · x² - (1/√2²) · y² = 2x² - 1/2 y²