`a) 5x – 7 = 23` `b) 2 – ( 3x – 7 )/4 + ( x + 17 )/5 = 0` `c) 4x + 5 = 3(x+2) + 4` `d) ( x – 1 )( x + 2 ) = 0`

2 bình luận về “`a) 5x – 7 = 23` `b) 2 – ( 3x – 7 )/4 + ( x + 17 )/5 = 0` `c) 4x + 5 = 3(x+2) + 4` `d) ( x – 1 )( x + 2 ) = 0`”

1. a) 5x – 7 = 23

   <=>5x = 30

   <=>x = 6

   Vậy S={6}

   b, 2 – (3x-7)/4 + (x+17)/5 = 0

   <=>40/20 – (15x+35)/20 + (4x+68)/20 = 0

   <=>40 – 15x + 35 + 4x + 68 = 0

   <=>-11x+143=0

   <=>-11x=-143

   <=>x=13

   Vậy S={13}

   c,4x+5 = 3(x+2) + 4

   <=>4x+5 = 3x + 6 + 4

   <=>4x-3x = 10 – 5

   <=>x = 5

   Vậy S={5}

   d,(x-1)(x+2) = 0

   <=>(x-1) = 0 hoặc (x+2) = 0

   <=>x= 1 hoặc x = -2

   Vậy S={1;-2}

   Trả lời
2. a,5x-7 = 23
   <=>5x = 30
   <=>x = 6
   Vậy S={6}
   b, 2 – (3x-7)/4 + (x+17)/5 = 0
   <=>40/20 – (5(3x-7))/20 + (4(x+17))/20 = 0
   <=>40 – 15x + 35 + 4x + 68 = 0
   <=>-15x + 4x = 0 -40 – 35 – 68
   <=>-11x = -143
   <=>x = 13
   Vậy S={13}
   c,4x+5 = 3(x+2) + 4
   <=>4x+5 = 3x + 6 + 4
   <=>4x-3x = 10 – 5
   <=>x = 5
   Vậy S={5}
   d,(x-1)(x+2) = 0
   <=>x-1=0 hoặc x+2=0
   <=>x=1 hoặc x=-2
   Vậy S={1;-2}

   Trả lời