中等MATH-INEQ-007
Solve 1 < 2x + 3 ≤ 9.
A. −1 ≤ x < 3
B. −1 < x < 3
C. −1 < x ≤ 3✓ 答案
D. 1 < x ≤ 3
解說
Subtract 3 to get −2 < 2x ≤ 6, then divide by 2: −1 < x ≤ 3. The left-hand inequality is strict and the right-hand inequality includes equality. Both ends do not become the same.