Question

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Answer 1

Răspuns:

Explicație pas cu pas:

2)  x/(x-7) => D = R-{7}

3) E(x) = (x+3)/(x+2) ; x ≠ -2 , pentru x = 2 =>

E(2) = (2+3)/(2+2) = 5/4

4) 4x²+2x = 2x·(2x+1)

5) 4x²-20x+25 = (2x-5)²

6) 5√3x+5√3y+2√7x+2√7y = 5√3(x+y) + 2√7(x+y) =

= (x+y)(5√3 + 2√7)

7) 12a³/6a ; a ≠ 0  => 12a³/6a = 2a²

8) (x²+3x+2)/(x²-2x-3) ; x ∈ R-{-1;3}

x²+3x+2 = x²+2x+x+2 = x(x+2)+(x+2) = (x+2)(x+1)

x²-2x-3 = x²-3x+x-3 = x(x-3)+(x-3) = (x-3)(x+1) =>

(x²+3x+2)/(x²-2x-3) =  [(x+2)(x+1)]/[ (x-3)(x+1)] = (x+2)/(x-3)

9) (x-5)/6x⁴ · 36x²/(x-5) = 36x²·(x-5)/[6x⁴·(x-5)] = 36x²/6x⁴ =

= 6/x²  ; x ∈ R-{0 ; 5}