Question

Tìm x:

a. \(\dfrac{x+2}{18}\) = \(\dfrac{-5}{9}\)

b.\(\dfrac{x+2}{18}\) =\(\dfrac{x-5}{9}\)

c.\(\dfrac{x+2}{-20}\) = \(\dfrac{-5}{x+2}\)

d. -10+ ( 2x + 5)³ =17

e.\(/3x+15/\) -28= 42

Answer 1

c. \(\dfrac{x+2}{-20}=\dfrac{-5}{x+2}\)

\(\Rightarrow\) x +2 . x + 2 = -5 . (- 20)

\(\left(x+2^{ }\right)^2\) = 100

\(\left(x+2^{ }\right)^2\) =\(10^2\)

\(\Rightarrow\) x + 2 = 10

x = 10 - 2

x = 8

Vậy x = 8

(Tick mk nha !!!)

Answer 2

d.-10+ (2x + 5)³ =17

(2x +5)³ =17-(-10)

(2x +5)³ =27

(2x +5)³ =3³

suy ra 2x +5 =3

2x =3-5

2x =-2

x =-2/2=-1

ko có dấu suy ra

Answer 3

b.suy ra x +2 .9 =x -5 .18

x +18 = x- 90

2x = 18-90

2x = -72

x = -72 :2

x = -36

Answer 4

tôi ko co dấu suy ra

nên viết chữ suy ra

Answer 5

a: =>x+2=-90/9=-10

=>x=-12

b: \(\Leftrightarrow\dfrac{x+2}{2}=\dfrac{x-5}{1}\)

=>2x-10=x+2

=>x=12

c: =>(x+2)^2=100

=>x+2=10 hoặc x+2=-10

=>x=-12 hoặc x=8

d: =>(2x+5)^3=27

=>2x+5=3

=>2x=-2

=>x=-1

e: =>|3x+15|=70

=>3x+15=70 hoặc 3x+15=-70

=>x=55/3 hoặc x=-85/3