a.(x-1) ² =1 b.275-(113+x)+63=158 c.565-13.x=370 d.105-(135-7x):9=97 e.[3.(x+2):7].4=120 f)x(x-1)=0 g.(x+2)(x-4)=0

2 bình luận về “a.(x-1) ² =1 b.275-(113+x)+63=158 c.565-13.x=370 d.105-(135-7x):9=97 e.[3.(x+2):7].4=120 f)x(x-1)=0 g.(x+2)(x-4)=0”

1. xin Câu tr lời hay nhất

   

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2. a, (x – 1)^2 = 1

   => (x – 1)^2 = (+-1)^2

   => x – 1 = 1 hoặc x – 1 = -1

   => x =2 hoặc x=  0

   Vậy x \in {0,2}

   b, 275 – (113 + x) + 63 = 158

   => 275 – 113 – x + 63 = 158

   => 225 – x = 158

   => x = 225 – 158

   => x = 67

   Vậy x = 67

   c, 565 – 13x = 370

   => 13x = 565 – 370

   => 13x = 195

   => x = 195 : 13

   => x=  15

   Vậy x=  15

   d, 105 – (135 – 7x) : 9 = 97

   => (135 – 7x) : 9 = 105 – 97

   => (135 – 7x) : 9 = 8

   => 135 – 7x = 8.9

   => 135 – 7x = 72

   => 7x = 135 – 72

   => 7x = 63

   => x = 63 : 7

   => x= 9

   Vậy x = 9

   e, [3.(x + 2) : 7] . 4 = 120

   => 3(x + 2) : 7 = 120 :4

   => 3(x + 2) : 7 = 30

   => 3(x + 2) = 30 . 7

   => 3(x + 2) = 210

   => x + 2 = 210 : 3

   => x + 2 = 70

   => x = 70 -2

   => x = 68

   Vậy x = 68

   f, x(x – 1) = 0

   => x =0 hoặc x – 1= 0

   => x = 0 hoặc x = 1

   Vậy x \in {0,1}

   g, (x + 2)(x – 4) = 0

   => x +2  = 0 hoặc x – 4= 0

   => x= -2 hoặc x =4

   vậy x \in {-2,4}

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