Răspuns:
Explicație pas cu pas:
16)
E ( x) = ( 3 - x ) / 2 x; x ∈ R\{0}
E(√2) = ( 3 - √2)/(2√2) = √2(3-√2)/4 = (3√2 - 2 )/4
E(- √2) = ( 3 + √2 )/-2√2 = - √2(3+√2)/4 = (-2-3√2)/4
E(√2) + E(-√2) = ( 3√2-2 - 2 -3√2)/4 = - 4/4 = - 1
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17.
(x-3)/(x+1) + 2/(x+1) = ( x - 3 + 2 ) / ( x + 1 ) = (x - 1 ) /(x+1); x ≠ - 1
-> adun numaratorii, deoarece fractiile au acelasi numitor
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18.
4/(x-1) - (3+x)/(x-1) = ( 4 - 3 - x )/(x-1) = ( 1 - x ) /( x - 1 ) = - 1; x ≠ 1
( - x + 1 ) /(x-1) = - ( x - 1 )/(x-1) = - 1
