Question

\(\left(\dfrac{3}{4}-x\right)^3=-8\)

Answer 1

\(\left(\dfrac{3}{4}-x\right)^3=-8\) (1)

\(\Leftrightarrow\left(\dfrac{3}{4}-x\right)^3=-2^3\)

\(\Leftrightarrow\left(\dfrac{3}{4}-x\right)=-2\)

\(\Leftrightarrow-x=-2-\dfrac{3}{4}\)

\(\Leftrightarrow-x=-\dfrac{11}{4}\)

\(\Leftrightarrow x=\dfrac{11}{4}\)

Vậy tập nghiệm phương trình (1) là \(S=\left\{\dfrac{11}{4}\right\}\)

Answer 2

\(\left(\dfrac{3}{4}-x\right)^3=-8\)

\(\Rightarrow\left(\dfrac{3}{4}-x\right)^3=-2^3\)

\(\Rightarrow\dfrac{3}{4}-x=-2\)

\(\Rightarrow x=\dfrac{3}{4}+2\)

\(\Rightarrow x=\dfrac{11}{4}\)