a)4.(2-x)+3.(x-5)=14 b)5.(x-3)-2.(x+6)=9 c)5.(x-7)+10.(3-x)=20 d)-4.(x+1)+8.(x-3)=24 e)4.(x-1)-3.(x-2)=-/-5/

0 bình luận về “a)4.(2-x)+3.(x-5)=14 b)5.(x-3)-2.(x+6)=9 c)5.(x-7)+10.(3-x)=20 d)-4.(x+1)+8.(x-3)=24 e)4.(x-1)-3.(x-2)=-/-5/”

1. Đáp án:

    

   Giải thích các bước giải:

    a) 4 . (2 – x) + 3 . (x – 5) = 14

   8 – 4x + 3x – 15 = 14

   -4x + 3x = 14 – 8 + 15

   -4x + 3x = 21

   x . (-4 + 3) = 21

   x. (-1) = 21

   x = 21 : (-1)

   x = -21

    Vậy x = -21

   b) 5 . (x – 3) – 2 . (x + 6) = 9

   5x – 15 – 2x- 12 = 9

   5x + 2x = 15+ 12 + 9

   5x + 2x = 36

   x . (5 – 2) = 36

   x . 3 = 36

   x = 36: 3

   x = 12

   vậy x = 12

   c) 5 . (x – 7) + 10 . (3 – x) = 20

   5x – 35 + 30 -10x = 20

   5x – 10x = 20 – 30 + 35

   5x – 10x = 25

   x . ( 5 – 10) = 25

   x . (-5) = 25

   x = 25 : (-5)

   x = -5

   Vậy x = – 5 

   d)-4 . (x + 1) + 8 . (x – 3) = 24

   -4x + 4 + 8x – 24 = 24 

   -4x + 8x = 4 + 24 + 24

   -4x + 8x = 52

   x . (-4 + 8) = 52

   x . 4 = 52

   x = 52 : 4

   x = 13

   Vậy x = 13

   e) 4 . (x – 1) – 3 . (x – 2) = -|-5|

   4x – 1 – 3x – 6 = -5

   4x – 3x = 1 + 6 – (-5)

   x . (4 – 3) + 2 = -5

   x . 1 + 2 = -5

   x . 1 = -5 – 2

   x . 1 = -7

   x = -7 : 1

   x = -7

   Vậy x = -7

   Trả lời

2. a) 4.(2-x)+3.(x-5)=14

   8-4x+3x-15=14

   -4x+3x=14+15-8

   -x=21

   x=-21

   b)5.(x-3)-2.(x+6)=9

   5x-15-2x-12=9

   5x-2x=9+12+15

   3x=36

   x=12

   c)5.(x-7)+10.(3-x)=20

   5x-35+30-10x=20

   5x-10x=20+35-30

   -5x=25

   x=-5

   d)-4.(x+1)+8.(x-3)=24

   -4x-4+8x-24=24

   -4x+8x=24+24+4

   4x=52

   x=13

   e) 4.(x-1)-3.(x-2)=-/-5/

   4x-4-3x+6=-/-5/

   4x-4-3x+6=-5

    4x-3x=-5-6+4

   x=-7

   Cho mk ctlhn nha. Cảm ơn bạn

   Trả lời