Question

Answer 1

a) \(5x^3=-40\Rightarrow x^3=-8=\left(-2\right)^3\Rightarrow x=-2\)

b) \(\left(8\dfrac{1}{2}x-5\right)^3=125=5^3\)\(\Rightarrow\dfrac{17}{2}x-5=5\Rightarrow\dfrac{17}{2}x=10\Rightarrow x=\dfrac{20}{17}\)

c) \(2.9^{x-1}=\dfrac{2}{9}\Rightarrow2.9^x=2\Rightarrow9^x=1\Rightarrow x=0\)

d) \(\left(x+\dfrac{2021}{2022}\right)^6=0\Rightarrow x+\dfrac{2021}{2022}=0\Rightarrow x=-\dfrac{2021}{2022}\)

Answer 2

a: =>x³=-8

=>x=-2

b: =>17/2x-5=5

=>17/2x=10

=>x=10:17/2=20/17

c: =>9^x-2=1/9

=>x-2=-1

=>x=1

d: =>x+2021/2022=0

hay x=-2021/2022

Answer 3

a) 5x^3 = -40

      x^3= -40: 5

      x^3=-8

      x^3=-2^3

 

Answer 4

(8 và 1/2x-5)^3 = 125

=>(17/2x-5)^3=5^3

=>17/2x-5=5

=>17/2x=10

    x=10:17/2

    x=20/17