Question

!!!!Am nevoie neaparat pentru maine!!! Va dau coroana

Answer 1

Răspuns:

Explicație pas cu pas:

a) (x+5)/x ; x ∈ R-{0}

x = 2 => (2+5)/2 = 7/2

b) (x-12)/[(x+1)(x-2)] ; x ∈ R-{-1 ; 2}

x = 1 => (1-12)/[(1+1)(1-2)] = -11/(-2) = 11/2

c) (3x²-2x+1)/[(2x-5)²-4x²] =  

= (3x²-2x+1)/[(2x-5-2x)(2x-5+2x)] =

= (3x²-2x+1)/[(-5)(4x-5)] ; x ∈ R-{5/4}

x = 0 => (0-0+1)/[(-5)·(0-5)] = 1/25

d) (2x+1)/(x²-x-20) = (2x+1)/(x²-5x+4x-20) =

= (2x+1)/[x(x-5)+4(x-5)] = (2x+1)/[(x-5)(x+4)] ; x ∈ R-{-4 ; 5}

x = -1 => (-2+1)/[(-7)·3] = -3/(-21) = 1/7

e) (x+y)/(x²+y²-4x+6y+13) = (x+y)/[(x²-4x+4)(y²+6y+9)] =

= (x+y)/[(x-2)²·(y+3)²]   => x ∈ R- {2} ; y ∈ R-{-3}

x = 0 ; y = 1 =>

(0+1)/(0+1-0+6+13) = 1/20