Đáp án:
Giải thích các bước giải:
bI
a, 2/x+1 +3/x-1 (1)
MTC =(X+1)(X-1)
(1)=2(X-1)/(x+1)(x-1) +3(x+1)/ (x-1)(x+1)
=2x-2+3x+3/(x+1)(x-1)
=5x+1/(x+1)(x-1)
b, 4x+5/2x-1 - 5-9x/2x-1
= 4x+5-5+9x/2x-1
=13x/2x-1
c, x+3/x²-1 + -x-1/x²-x
=x+3/(x-1)(x+1) +-x-1/x(x-1)
MTC (x-1)(x+1)x
= (x+3)x/(x-1)(x+1)x + (-x-1)(x+1)/(x+1)(x-1)x
=x²+3x/(x-1)(x+1)x -x²-2x-1/(x+1)(x-1)x
=x-1/(x-1)(x+1)x
=1/(x+1)x
d,=3/2(x+3) - x-6/2x(x+3)
MTC 2x(x+3)
= 3x/2x(x-3) - x-6/2x(x+3)
=2x+6/2x(x+3)
=2(x+3) /2x(x+3)
=1/x
Bai II
a, = 7xy / xy
= 7
b, = (x-6)(x+6) / 2x+10 . (-3/x-6)
=(x-6)(x+6)(-3)/ (2x+10)(x-6)
=-3x+18/ 2x+10
c,=5(x+2)/4(x-2) . (-2x-4/x+2)
=5(x+2)/4(x-2) . [-2(x-2)/x+2]
= 5(x+2)[-2(x-2)] / 4(x-2)(x+2)
=-10/4 =-5/2
d,=3xy-1/x+1 + 3xy+9/(x-1)(x+1)
MTC (x-1)(x+1)
=(3xy-1)(x-1)/(x-1)(x+1) + 3xy+9/(x-1)(x+1)
=3x^2-3xy-x+1+3xy+9/(x-1)(x+1)
=3x^2-x+10/(x-1)(x+1)
