Răspuns:
Explicație pas cu pas:
a)
E(x) = [ 3 x / (x + 1 ) - 1 ] : [ 1 + 3 x² / (x² - 1) ]
E(x) = [(3 x - x - 1) / ( x + 1)] : [ ( x² - 1 + 3 x² ) / ( x² - 1 ) ]
E(x) = [ ( 2 x - 1 ) / ( x + 1 ) ] : [ ( 4 x² - 1 ) / ( x² - 1 ) ]
E(x) = [ ( 2 x - 1 ) / ( x + 1 ) ] × [ ( x² - 1 ) / ( 4 x² - 1) ]
E( x) = [ ( 2 x - 1 ) / ( x + 1 ) ] × [ ( x + 1) ( x + 1 ) / ( 2 x - 1 ) ( 2 x + 1 ) ]
E( x ) = ( x - 1 ) / ( 2 x + 1 ) √
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b)
2 × E( x ) - 7 = 0
2 × ( x - 1 ) / ( 2 x + 1 ) = 7
7 ( 2 x + 1 ) = 2 ( x - 1 )
14 x + 7 = 2 x - 2
14 x - 2 x = - 2 - 7
12 x = - 9
x = - 9 / 12
x = - 3 / 4
