Question

Bài 1:Tìm x

a,\(x^2=16\)

b,\(\left(x-\dfrac{1}{2}\right)^3=\dfrac{1}{27}\)

c,\(3^3.x=3^6\)

d,\(\dfrac{1,35}{0,2}=\dfrac{1,25}{x}\)

Answer 1

a) x² = 16

\(\Rightarrow\) x = \(\pm\sqrt{16}\)

\(\Rightarrow\) x = \(\pm\)4

Answer 2

b) (x - \(\dfrac{1}{2}\))³ = \(\dfrac{1}{27}\)

\(\Rightarrow\) x - \(\dfrac{1}{2}\) = \(\sqrt{\dfrac{1}{27}}\)

\(\Rightarrow\) x - \(\dfrac{1}{2}\) = \(\dfrac{1}{3}\)

\(\Rightarrow\) x = \(\dfrac{5}{6}\)

Answer 3

a) \(x^2=16\)

\(\Rightarrow x^2=4^2\) hoặc \(x^2=\left(-4\right)^2\)

\(\Rightarrow x=4\) hoặc \(x=-4\)

Vậy .....

b) \(\left(x-\dfrac{1}{2}\right)^3=\dfrac{1}{27}\)

\(\Rightarrow x-\dfrac{1}{2}=\dfrac{1}{3}\)

\(\Rightarrow x=\dfrac{5}{6}\)

Vậy ........

c) \(3^3.x=3^6\)

\(\Rightarrow x=3^3\)

\(\Rightarrow x=27\)

Vậy. ...

d) \(\dfrac{1,35}{0,2}=\dfrac{1,25}{x}\)

\(\Rightarrow\dfrac{27}{\dfrac{20}{\dfrac{1}{5}}}=\dfrac{5}{\dfrac{4}{x}}\)

\(\Rightarrow\dfrac{27}{4}=\dfrac{5}{4x}\)

\(\Rightarrow27.4x=4.5\)

\(\Rightarrow108x=20\)

\(\Rightarrow x=\dfrac{5}{27}\)

Vậy ....

Answer 4

c) 3³ . x = 3⁶

\(\Rightarrow\) x = 3⁶ : 3³ = 3^{6 - 3}

\(\Rightarrow\) x = 3³

\(\Rightarrow\) x = 27

Answer 5

\(a,x^2=16\)

\(\rightarrow x^2=4^2\)

\(\rightarrow x=4\)

Vậy x =4

b,\(\left(x-\dfrac{1}{2}\right)^3=\dfrac{1}{27}\)

\(\rightarrow\left(x-\dfrac{1}{2}\right)^3=\left(\dfrac{1}{3}\right)^3\)

\(\rightarrow x-\dfrac{1}{2}=\dfrac{1}{3}\)

\(x=\dfrac{1}{3}+\dfrac{1}{2}\)

\(x=\dfrac{5}{6}\)

Vậy x=\(\dfrac{5}{6}\)

c,\(3^3.x=3^6\)

\(x=3^6:3^3\)

\(x=3^3\)

\(\rightarrow x=27\)

Vậy x=27

d,\(\dfrac{1,35}{0,2}=\dfrac{1,25}{x}\)

\(\rightarrow1,35.x=0,2.1,25\)

\(1,35.x=0,25\)

\(x=0,25:1,35\)

\(x=\dfrac{5}{27}\)

Vậy x=\(\dfrac{5}{27}\)