1)5.(x-3)-2.(x+6)=9 2)5.(x-7)+10(5-x)=20 3)-4.(x+1)+8(x-3)=24 4)7(5x)+5(x-2)=15 5)4(x-1)-3(x-2)=-/-5/

0 bình luận về “1)5.(x-3)-2.(x+6)=9 2)5.(x-7)+10(5-x)=20 3)-4.(x+1)+8(x-3)=24 4)7(5x)+5(x-2)=15 5)4(x-1)-3(x-2)=-/-5/”

1. 1) 5.(x-3)-2.(x+6)=9 

   <=> 5x – 15 – (2x+12) =9

   ⇔ 5x -15 – 2x – 12 – 9 = 0

   ⇔ 3x – 36 = 0

   ⇔ 3 (x-12) = 0

   ⇔ x = 12

   Vậy x=12

   2)5.(x-7)+10(5-x)=20

   ⇔5x – 35 + 50 – 10x = 20

   ⇔-5x + 15 = 20

   ⇔-5x = 20-15 = 5

   ⇔ x = -1

   Vậy x=-1

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

   ⇔-4x – 4 + 8x – 24 = 24

   ⇔ 4x – 28 = 24

   ⇔ 4x = 24+28 = 52

   ⇔ x = 13

   Vậy x = 13

   4)7(5x)+5(x-2)=15

   ⇔ 35x + 5x – 10 = 15

   ⇔ 40x = 15 + 10 = 25

   ⇔ x = $\frac{5}{8}$ 

   vậy x = $\frac{5}{8}$ 

   5)4(x-1)-3(x-2)=-/-5/

   ⇔ 4x – 4 – 3x + 6 = -(-5) = 5

   ⇔ x + 2 = 5

   ⇔ x = 3

   Vậy x = 3

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2. Đáp án+Giải thích các bước giải:

   `1)5(x-3)-2(x+6)=9`

   `=>5x-15-2x-12=9`

   `=>3x-27=9`

   `=>3x=36`

   `=>x=12`

   Vậy `x=12`

   `2)5(x-7)+10(5-x)=20`

   `=>5x-35+50-10x=20`

   `=>-5x+15=20`

   `=>-5x=5`

   `=>x=-1`

   Vậy `x=-1`

   `3)-4(x+1)+8(x-3)=24`

   `=>-4x-4+8x-24=24`

   `=>4x-28=24`

   `=>4x=52`

   `=>x=13`

   Vậy `x=13`

   `4)7.5x+5(x-2)=15`

   `=>35x+5x-10=15`

   `=>40x=25`

   `=>x=5/8`

   Vậy `x=5/8`

   `5)4(x-1)-3(x-2)=-|-5|`

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

   `=>x+2=-5`

   `=>x=-7`

   Vậy `x=-7`

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