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Cô Thu Hà

Tìm x, biết:

a)$x+\dfrac{1}{2}=\dfrac{6}{4}$

b) ${{x}^{4}}{{.3}^{5}}={{27}^{3}}$ c) $\dfrac{8}{3}.(\dfrac{5}{24}-x )=\dfrac{-1}{3}$

456
Hôm kia lúc 15:52

\(a,x+\dfrac{1}{2}=\dfrac{6}{4}\)

\(\Rightarrow x=\dfrac{6}{4}-\dfrac{1}{2}\)

\(\Rightarrow x=\dfrac{6}{4}-\dfrac{2}{4}\)

\(\Rightarrow x=1\)

Vậy `x = 1`

\(b,x^4\cdot3^5=27^3\)

\(\Rightarrow x^4\cdot3^5=\left(3^3\right)^3\)

\(\Rightarrow x^4\cdot3^5=3^9\)

\(\Rightarrow x^4=3^9:3^5\)

\(\Rightarrow x^4=3^4\)

\(\Rightarrow x=3\)

Vậy \(x=3\)

\(c,\dfrac{8}{3}\cdot\left(\dfrac{5}{24}-x\right)=\dfrac{-1}{3}\)

\(\Rightarrow\dfrac{5}{24}-x=\dfrac{-1}{3}:\dfrac{8}{3}\)

\(\Rightarrow\dfrac{5}{24}-x=\dfrac{-1}{8}\)

\(\Rightarrow x=\dfrac{5}{24}-\dfrac{-1}{8}\)

\(\Rightarrow x=\dfrac{5}{24}+\dfrac{1}{8}\)

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

Vậy \(x=\dfrac{1}{3}\)