all x ∈ R that satisfy |x+1|-2|x-4|= 3
help?
In this problem, use cases.
$\displaystyle \begin{array}{l}
x \in ( - \infty , - 1]\quad \Rightarrow \quad \left( { - x - 1} \right) - 2\left( { - x + 4} \right) = 3 \\
x \in ( - 1,4)\quad \Rightarrow \quad \left( {x + 1} \right) - 2\left( { - x + 4} \right) = 3 \\
x \in [4,\infty )\quad \Rightarrow \quad (x + 1) - 2(x - 4) = 3 \\
\end{array}$
Now solve each of the three cases.
But make sure the solution fits the case.