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2013-05-26T21:52:12+02:00

2)

A = 9x² - 3xy² + x (x - y)

x = -1 ; y = -2

 

A = 9 x (-1)² - 3 x (-1) x (-2)² + (-1)² + (-1) x 2

A = 9 + 6 + 1 - 2

A = 14

 

3)

B = (a+b²) / 2ab²

a = 5/6 ; b = -1/3

 

B = (5/6 + (-1/3)²) / 2 x 5/6 x (-1/3)²

B = (5/6 + 1/9) / 10/6 x 1/9

B = (17/18) / (5/27) = 51/10 = 5,1