−1≤x≤7-1 \leq x \leq 7−1≤x≤7
1≤x≤71 \leq x \leq 71≤x≤7
−7≤x≤1-7 \leq x \leq 1−7≤x≤1
−7≤x≤−1-7 \leq x \leq-1−7≤x≤−1