Toán Lớp 6: HELP ME PLEASEE Bài 1 : a. 2.(-x+2 )+( -4)=(-14) b. 240 : (x-4) = 17+(-9) c. 2.(x+3)^3-200 = 2.5^2

TRẢ LỜI

1. a,

   2.(-x+2)+(-4)=(-14)

   2.(-x)+4-4=-14

   2.(-x)=-14

   -x=-14:2

   -x=-7

   x=7

   b,

   240:(x-4)=17+(-9)

   240:(x-4)=8

   x-4=240:8

   x-4=30

   x=34

   c,

   2.(x+3)^3-200=2.5^2

   2.(x+3)^3-200=50

   2.(x+3)^3=250

   (x+3)^3=250:2

   (x+3)^3=125

   (x+3)^3=5^3

   x+3=5

   x=2

   Trả lời
2.  1.

   a, 2(-x + 2) + (-4) = -14

   => 2(-x + 2) = -14 – (-4)

   => 2(-x + 2) = -10

   => -x + 2 = -10 : 2

   => -x + 2 = -5

   => -x = -5 – 2

   => -x = -7

   => x = 7

   Vậy x = 7

   b, 240 : (x – 4) = 17 + (-9)

   => 240 : (x – 4) = 8

   => x – 4 = 240 : 8

   => x – 4 = 30

   => x = 34

   Vậy x = 34

   c, 2(x + 3)^3 – 200 = 2. 5^2

   => 2(x + 3)^3 – 200 = 2. 25

   => 2(x + 3)^3 – 200 = 50

   => 2(x + 3)^3 = 50 + 200

   => 2(x + 3)^3 = 250

   => (x + 3)^3 = 125

   => (x + 3)^3 = 5^3

   => x + 3 = 5

   => x = 5-3 = 2

   Vậy x = 2

   Trả lời