Answer
Fill the blank with$:$
middle of the compound inequality
Work Step by Step
The idea is to isolate x in the middle of the compound inequality
Adding, subtracting or multiplying/dividing with a positive number preserves order (the inequality symbol remains).
Multiplying/dividing with a negative number inverts the order (the inequality symbol changes).
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We would first add 4 to all parts of the compound inequality:
$-3 \lt 3x \leq 9$
... then divide all parts with 3 (positive, direction remains the same.)
$-1\lt x \leq 3$
