Inequality Intuition Math Example 2

Follow the full solution, then compare it with the other examples linked below.

Example 2

medium
Solve \(-2x \geq 8\) and explain the direction flip when multiplying by a negative.

Solution

  1. 1
    Divide both sides by \(-2\). When dividing by a negative, flip the inequality.
  2. 2
    \(-2x \geq 8 \Rightarrow x \leq -4\).
  3. 3
    Solution: all \(x \leq -4\).
  4. 4
    Check with \(x=-6\): \(-2(-6) = 12 \geq 8\) βœ“; check \(x=-4\): \(-2(-4)=8 \geq 8\) βœ“.

Answer

\(x \leq -4\)
Dividing or multiplying an inequality by a negative number flips the inequality direction. This preserves the truth of the statement.

About Inequality Intuition

Understanding that << and >> describe ordering relationshipsβ€”one quantity is strictly smaller or larger than the other.

Learn more about Inequality Intuition β†’

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