a. x+4/5-x+4=x/3-x-2/2 b.4x+3/5-6x-2/7=5x+4/3+3 c. 5x+2/6-8x-1/3=4x+2/5-5

0 bình luận về “a. x+4/5-x+4=x/3-x-2/2 b.4x+3/5-6x-2/7=5x+4/3+3 c. 5x+2/6-8x-1/3=4x+2/5-5”

1. a/3x+2/ 2-3x+1/6=5/3+2x   ( x khác  2/3)

   <=> 3x + 2/ 2-3x +1/6 – 5/3 – 2x = 0

   <=> 3x + 2/ 2-3x – 3/2 – 2x = 0

   <=> 2 ( 3x + 2 ) – 3 ( 2 – 3x) – 4x ( 2 – 3x ) / 2 ( 2 – 3x ) = 0

   <=> 6x + 4 – 6 + 9x – 8x + 12x^2 / 2 ( 2 – 3x ) = 0 

   <=>  7x – 2 + 12x^2 = 0 

   <=> 12x^2 + 7x – 2 = 0

   <=> x = -7 cộng trừ căn bậc 7^2 – 4 . 12 . ( – 2) / 2 . 12

   <=> x = -7 cộng trừ căn bậc 49 + 96 / 24

   <=>  x = – 7 cộng trừ căn bậc 145 / 24 

   b/4x+3/5-6x-7/2=5x+4/3+3 ( x khác 5/6 ) 

   <=> 4x + 3 / 5 – 6x – 7/2 – 5x + 4 / 6 = 0

   <=> 6 ( 4x + 3 ) – 21 ( 5 – 6x ) – ( 5 – 6x ) ( 5x + 4 ) / 6 ( 5 – 6x ) = 0

   <=> 24x + 18 – 105 + 126x – ( 25x + 20 – 30x^2 – 24x ) / 6 ( 5 – 6x ) = 0

   <=> 24x + 18 – 105 + 126x – ( x + 20 – 30x^2 ) / 6 ( 5 – 6x ) = 0

   <=> 24x + 18 – 105 + 126x –  x – 20 + 30x^2  / 6 ( 5 – 6x ) = 0

   <=> 149x – 107 + 30x^2 / 6 ( 5 – 6x ) = 0

   <=> 149x – 107 + 30x^2 = 0

   <=> x = – 149 cộng trừ căn bậc 149^2 – 4 . 30 . ( – 107 ) / 2. 30

   <=> x = – 149 cộng trừ căn bậc 35041 / 60

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2. `a, (x+4)/5-x+4=x/3-(x-2)/2`
   `<=>(6(x+4))/30-(30(x+4))/30=(10x)/30-(15(x-2))/30`
   `<=>6x+24-30x+120=10x-15x+30`
   `<=>6x+24-30x+120=10x-15x+30`
   `<=>144-24x=30-5x`
   `<=>114=19x`
   `<=>x=6`

   Vậy `x=6`

   `b,(4x+3)/5-(6x-2)/7=(5x+4)/3+3`
   `<=>(21(4x+3))/105-(15(6x-2))/105=(35(5x+4))/3+315/105`
   `<=>84x+63-90x+30=175x+140+315`
   `<=>93-6x=175x+455`
   `<=>362=-181x`
   `<=>x=-2`

    Vậy `x=-2`

   `c, (5x+2)/6-(8x-1)/3=(4x+2)/5-5`
   `<=>(5(5x+2))/30-(10(8x-1))/30=(6(4x+2))/30-150/30`
   `<=>25x+10-80x+10=24x+12-150`
   `<=>20-55x=24x-138`
   `<=>158=79x`
   `<=>x=2`

   Vậy `x=2`

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