Wykonaj działania:
a)
b)
c)
d)
e)
(x+2)/(x^2 -9) - (x+4)/(x+3) = (x+2)/[(x+3)(x-3)] - (x+4)(x-3)/[(x+3)(x-3)] =
D = R \ {-3; 3}
= [x+2 -(x+4)(x-3)]/(x^2 -9) = [x+2 -(x^2 -3x+4x-12)]/(x^2 -9) =
= [x^2 + 2 -(x^2 +x-12)]/(x^2 -9) = (x^2 + 2-x^2 -x+12)/(x^2 -9) =
= (14-x^2)/(x^2-9) = (V14 +x)(V14 -x)/[(x+3)(x-3)]
(3x-1)/(x+2) + (x^2 -2)/(x^2 -4) = (3x-1)/(x+2) + (x^2 -2)/[(x+2)(x-2)] =
D = R \ {-2; 2}
= [(3x-1)(x-2) + x^2 -2]/(x^2 -4) = (3x^2 - 6x - x +2 +x^2 -2)/(x^2 -4) =
= (4x^2 - 7x)/(x^2 - 4) = [2x+V(7x)]*[2x-V(7x)]/[(x+2)(x-2)]
4x/(x+6) - (x+5)/(x^2 + 6x) = 4x/(x+6) - (x+5)/[x(x+6)] =
D = R \ {0; -6}
= [4x*x -(x+5)(x+6)]/(x^2 + 6x) = [4x^2 -(x^2 + 6x+5x+30)]/(x^2 + 6x) =
= (4x^2 - x^2 -11x -30)/(x^2 + 6x) = (3x^2 -11x -30)/(x^2 +6x)
(2x+1)/(x+2) - (x^2 +5)/(x^2 -x -6)=
x^2 -x -6 =0
D = 1+24 = 25
VD = 5
x1 = (1-5)/2 = -2
x2 = (1+5)/2 = 3
D= R \ {-2;, 3}
x^2 - x - 6 = (x+2)(x-3)
= [(2x+1)(x-3) - x^2 - 3]/(x^2 -x-6) = (2x^2 - 6x +x -3 - x^2 -3)/(x^2 -x -6) =
= (x^2 - 5x -6)/(x^2 - x - 6) = (x+1)(x-6)/[(x+2)(x-3)
(6x+2)/(x+5) - (x^2 -4)/(x^2 +10 + 215) = (6x+2)/(x+5) - (x^2 -4)/[(x+5)^2] =
D = R \ {-5}
= [[(6x+2)(x+5) - (x^2 -4)]/[(x+5)^2] =
= (6x^2 +30x + 2x +10 - x^2 + 4)/(x^2 +10x + 25) =
= (5x^2 + 32x +14)/(5x^2 +10x + 25)
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a)
b)
c)
d)
e)
a)
(x+2)/(x^2 -9) - (x+4)/(x+3) = (x+2)/[(x+3)(x-3)] - (x+4)(x-3)/[(x+3)(x-3)] =
D = R \ {-3; 3}
= [x+2 -(x+4)(x-3)]/(x^2 -9) = [x+2 -(x^2 -3x+4x-12)]/(x^2 -9) =
= [x^2 + 2 -(x^2 +x-12)]/(x^2 -9) = (x^2 + 2-x^2 -x+12)/(x^2 -9) =
= (14-x^2)/(x^2-9) = (V14 +x)(V14 -x)/[(x+3)(x-3)]
b)
(3x-1)/(x+2) + (x^2 -2)/(x^2 -4) = (3x-1)/(x+2) + (x^2 -2)/[(x+2)(x-2)] =
D = R \ {-2; 2}
= [(3x-1)(x-2) + x^2 -2]/(x^2 -4) = (3x^2 - 6x - x +2 +x^2 -2)/(x^2 -4) =
= (4x^2 - 7x)/(x^2 - 4) = [2x+V(7x)]*[2x-V(7x)]/[(x+2)(x-2)]
c)
4x/(x+6) - (x+5)/(x^2 + 6x) = 4x/(x+6) - (x+5)/[x(x+6)] =
D = R \ {0; -6}
= [4x*x -(x+5)(x+6)]/(x^2 + 6x) = [4x^2 -(x^2 + 6x+5x+30)]/(x^2 + 6x) =
= (4x^2 - x^2 -11x -30)/(x^2 + 6x) = (3x^2 -11x -30)/(x^2 +6x)
d)
(2x+1)/(x+2) - (x^2 +5)/(x^2 -x -6)=
x^2 -x -6 =0
D = 1+24 = 25
VD = 5
x1 = (1-5)/2 = -2
x2 = (1+5)/2 = 3
D= R \ {-2;, 3}
x^2 - x - 6 = (x+2)(x-3)
= [(2x+1)(x-3) - x^2 - 3]/(x^2 -x-6) = (2x^2 - 6x +x -3 - x^2 -3)/(x^2 -x -6) =
= (x^2 - 5x -6)/(x^2 - x - 6) = (x+1)(x-6)/[(x+2)(x-3)
e)
(6x+2)/(x+5) - (x^2 -4)/(x^2 +10 + 215) = (6x+2)/(x+5) - (x^2 -4)/[(x+5)^2] =
D = R \ {-5}
= [[(6x+2)(x+5) - (x^2 -4)]/[(x+5)^2] =
= (6x^2 +30x + 2x +10 - x^2 + 4)/(x^2 +10x + 25) =
= (5x^2 + 32x +14)/(5x^2 +10x + 25)