Question

|5³ +3|x+1|=2*4³

Answer 1

\(\left|5^3+3\left|x+1\right|\right|=2.4^3\)

\(\Leftrightarrow\left|5^3+3\left|x+1\right|\right|=128\)

\(\Leftrightarrow5^3+3\left|x+1\right|=128\) hay \(5^3+3\left|x+1\right|=-128\)

\(\Leftrightarrow3\left|x+1\right|=3\) hay \(3\left|x+1\right|=-253\)

\(\Leftrightarrow\left|x+1\right|=1\) hay \(\left|x+1\right|=\dfrac{-253}{3}\) (vô lí do \(\left|x+1\right|\ge0\forall x\))

\(\Leftrightarrow x+1=1\) hay \(x+1=-1\)

\(\Leftrightarrow x=0\) hay \(x=-2\)

-Vậy \(S=\left\{0;-2\right\}\)