a.(4x-3)-3(x+5)+4(x-10)=5(x+2) b.11/12-(2/5+x)=2/3(6x+1) c.2x+1/3=1/2 d.(1/7x-2/7).(-1/5x+3/5).(1/3x+4/3)=0 1/6x+1/10x-4/5x+1=0 |5/3x|=|-1/6| |3/4x-3

0 bình luận về “a.(4x-3)-3(x+5)+4(x-10)=5(x+2) b.11/12-(2/5+x)=2/3(6x+1) c.2x+1/3=1/2 d.(1/7x-2/7).(-1/5x+3/5).(1/3x+4/3)=0 1/6x+1/10x-4/5x+1=0 |5/3x|=|-1/6| |3/4x-3”

1. Đáp án:

    

   Giải thích các bước giải:

   a.(4x-3)-3(x+5)+4(x-10)=5(x+2)

   <=> 4x-3-3x-15+4x-40=5x+2

   <=> 5x-58=5x+2

   <=> -60 = 0 (vô lí)

   vậy pt vô nghiệm

   c) 2x +1/3 = 1/2            msc:6

   <=> 12x/6 + 2/6 = 3/6

   <=> 12x+2 = 3

   <=> 12x = 1 

   <=> x=1/12

   vậy S={1/12}

   d) (1/7x-2/7).(-1/5x+3/5).(1/3x+4/3)=0

   <=> 1/7x – 2/7 = 0  ;  -1/5x+3/5=0 ; 1/3x + 4/3=0

   <=> 1-2x=0 ;  -1+3x=0;  1+4x=0

   <=> x=1/2 ; x=1/3; x= -1/4

   vậy S={1/2; 1/3; -1/4}

   e) 1/6x+1/10x-4/5x+1=0    mtc: 30x      đkxđ: x khác 0

   <=> 5/30x + 3/30x – 24/30x + 30x/30x = 0

   <=> -16 + 30x = 0

   <=> 30x = 16

   <=> x = 8/15

    vậy S={8/15}

   <=> 

   Bình luận