Question

Calculati |x − 2| + |x + 1| , daca x ∈ [−1, 2].

Answer 1

$\displaystyle x\in[-1;2] \\ \\ \implies -1\leq x\leq 2 \\ \\ -1\leq x\leq 2|-2\implies -3\leq x-2\leq 0\implies |x-2|=-x+2 \\ \\ -1\leq x\leq 2|+1\implies 0\leq x+1\leq 3\implies |x+1|=x+1 \\ \\ |x-2|+|x+1|=-x+2+x+1=3$