Răspuns:
Explicație pas cu pas:
(7x²-19) /[(5-x)(x+3)]
5-x ≠ 0 => x ≠ 5
x+3 ≠ 0 => x ≠ -3 => x ∈ R-{-3 ; 5}
E(x) = [2x/(5x-1) + 1] : [(49x²-1) / (25x²-10x+1)]
Enuntul are o eroare : 25x²-10x+1
5x-1 ≠ 0 => x ≠ 1/5
49x²-1 ≠ 0 <=> (7x+1)(7x-1) ≠ 0 => x ≠ {-1/7 ; 1/7}
25x²-10x+1 ≠ 0 <=> (5x-1)² ≠ 0 => x ≠ 1/5
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E(x) = [(2x+5x-1)/(5x-1)] ·{(5x-1)/[(7x-1)(7x+1)]}
E(x) = (7x-1)/[(7x-1)(7x+1)] = 1/(7x+1)
x ∈ R-{-1/7 ; 1/5 ; 1/7}
