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How do you solve a linear inequality in one variable, when do you flip the sign, and how do you graph and interpret the solution?

Solve linear inequalities in one variable, including those requiring the distributive property and those with variables on both sides, graph the solution, and interpret it in context (TEKS A.5B).

A STAAR Algebra I answer on solving one-variable linear inequalities (TEKS A.5B), the rule for flipping the sign when multiplying or dividing by a negative, graphing on a number line, and interpreting in context.

Generated by Claude Opus 4.89 min answer

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  1. What this topic is asking
  2. Solve like an equation, with one rule
  3. Graphing the solution on a number line
  4. Variables on both sides
  5. Interpreting in context
  6. How STAAR examines this topic
  7. Compound inequalities and "at least / at most" language
  8. Try this

What this topic is asking

TEKS A.5B is the inequality companion to solving equations, in the same heavily weighted Reporting Category 3. You solve a one-variable inequality almost exactly like an equation, with one extra rule, then graph the solution on a number line and interpret it in context. The redesigned test often makes the graph itself the answer through a hot-spot item.

Solve like an equation, with one rule

The steps mirror equation-solving: distribute, combine like terms, collect the variable, and divide. The one difference is the sign-flip rule.

For 4x1<114x - 1 < 11: add 1 to get 4x<124x < 12, divide by positive 4 (no flip) to get x<3x < 3. For 5x20-5x \le 20: divide by 5-5 and flip to get x4x \ge -4.

Graphing the solution on a number line

The solution to a one-variable inequality is a ray (or interval) on the number line.

  • Circle style. Open circle for a strict inequality (<< or >>); closed circle for \le or \ge.
  • Direction. Shade toward the solutions: right for >> or \ge, left for << or \le, once the variable is alone on the left.

So x>28x > 28 is an open circle at 28 with a ray to the right; x4x \le -4 is a closed circle at 4-4 with a ray to the left.

Variables on both sides

Collect the variable on one side first, then apply the rule only if the final division is by a negative.

Interpreting in context

In a real-world inequality, finish with a sentence. A solution m>5m > 5 months means "from month 6 onward"; a solution s20s \le 20 items means "at most 20 items". Where only whole numbers make sense, state the smallest or largest acceptable whole number, the interpretive credit the standard rewards.

How STAAR examines this topic

  • Multiple choice. Solve an inequality; the "forgot to flip" answer is always offered.
  • Hot spot. Build the number-line graph (circle style plus ray direction), both of which must be correct.
  • Inline choice and number entry. State a boundary value or choose the correct symbol.

A clarifying idea is why the sign flips: multiplying by a negative reverses the order of numbers (for example 2<52 < 5 but 2>5-2 > -5), so to keep the statement true the symbol must turn around.

Compound inequalities and "at least / at most" language

Some inequalities have two bounds, written as a compound statement. "Between 10 and 20 inclusive" is 10x2010 \le x \le 20, graphed as a segment with closed circles at both ends. You solve each part the same way, applying any operation to all three regions at once: from 12x35-1 \le 2x - 3 \le 5, add 3 throughout to get 22x82 \le 2x \le 8, then divide by 2 to get 1x41 \le x \le 4.

Translating the everyday phrasing is its own assessed skill. "At least" means \ge, "at most" means \le, "more than" means >>, and "no more than" means \le. A budget that allows spending "no more than \50"becomesa50" becomes a \le 50$ constraint, and the solution describes every affordable amount. Reading these phrases as the correct symbol is where many context inequalities are won or lost, because the rest of the algebra is routine once the symbol is right.

Try this

Q1. Solve 4x+3<19-4x + 3 < 19. [1 point]

  • Cue. 4x<16x>4-4x < 16 \Rightarrow x > -4 (flip on dividing by 4-4).

Q2. Graph x2x \ge 2 on a number line. [1 point]

  • Cue. Closed circle at 2, ray to the right.

Exam-style practice questions

Practice questions written in the style of TEA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

STAAR (style)1 marksMultiple choice. What is the solution to 3x+517-3x + 5 \ge 17? (A) x4x \le -4 (B) x4x \ge -4 (C) x4x \le 4 (D) x4x \ge 4
Show worked answer →

The correct answer is (A).

Subtract 5: 3x12-3x \ge 12. Divide both sides by 3-3, and because you divide by a negative, flip the inequality: x4x \le -4. Forgetting to flip gives x4x \ge -4 (choice B), the single most common inequality error. Adding or subtracting never flips the sign; only multiplying or dividing by a negative does.

STAAR (style)2 marksHot spot. A delivery driver must make more than 40 stops to earn a bonus. They have made 12 stops and average no fewer than the rest. Solve 12+s>4012 + s > 40 for ss, then select the graph: an open or closed circle at 28 with a ray to the right or left.
Show worked answer →

The solution is s>28s > 28: an open circle at 28 with the ray pointing right.

Subtract 12 from both sides: s>28s > 28. The strict symbol >> means 28 itself is not included, so the circle is open (not filled). The solution is all values greater than 28, so the ray points right. A closed circle would require \ge, and a leftward ray would represent <<; both are distractors on the hot-spot item.

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