ACT Math · Linear equations and inequalities

Solve the compound inequality: -5 < 2x + 3 ≤ 9.

Solve the compound inequality: −5<2x+3≤9-5 < 2x + 3 \leq 9.

Answer and explanation

Answer: A: -4 < x ≤ 3

Do the same operation on all three parts. Subtract 33: −8<2x≤6-8<2x\le6. Divide by 22 (positive, so no reversal): −4<x≤3-4<x\le3, choice A. Choice D (−8<x≤3-8<x\le3) forgets to divide the left part by 22. Choice B (−4<x≤6-4<x\le6) forgets to divide the right part by 22. Choice C (−1<x≤6-1<x\le6) adds 33 instead of subtracting it, then divides. Test x=3x=3: 2(3)+3=92(3)+3=9, which equals the upper bound, so 33 is included, consistent with the symbol ≤\le.

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