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      Solving more complicated linear inequalities

      Lesson details

      Learning outcome

      I can solve more complicated linear inequalities.

      Key learning points

      1. Inequalities can be combined to be more efficient
      2. By treating the combined inequality as two separate inequalities, you can easily solve
      3. There may be a set of possible values, inequality notation can be used to communicate them efficiently

      Keywords

      • Inequality - An inequality is used to show that one expression may not be equal to another.

      Common misconception

      Dividing or multiplying by -1 does not change the inequality sign.

      2 < 3 becomes -2 > -3 when both sides are multiplied by -1.

      Teacher tip

      Pupils may need to review their understanding of solving equations before completing this lesson. The previous lesson is a good starting point for dealing with multiplying by -1 if pupils need a quick recap.

      Licence

      This content is © Oak National Academy Limited (2025), licensed on Open Government Licence version 3.0
      except where otherwise stated. See Oak's terms & conditions
      (Collection 2).

      Lesson video

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      Prior knowledge starter quiz

      6 Questions

      Q1.
      Which of these shows the solutions to the inequality $$3<2x+1$$?

      $$x<1$$
      Correct answer: $$x>1$$
      $$x<2$$
      $$x>2$$

      Q2.
      The solution to $$\frac{x+5}{3} \ge 3$$ is when $$x \ge $$

      Correct Answer: 4

      Q3.
      Which of these values satisfy the inequality $$3 < x \le 4 $$ ?

      $$x=2.5$$
      $$x=3$$
      Correct answer: $$x=3.5$$
      Correct answer: $$x=4$$
      $$x=4.5$$

      Q4.
      Which of these values satisfy the inequality $$-3 < x < -2 $$ ?

      $$x=-3$$
      $$x=-2$$
      $$x=-3.5$$
      Correct answer: $$x=-2.5$$
      $$x=-1.5$$

      Q5.
      If $$-x > 3$$ which of the following is an equivalent inequality?

      $$x<3$$
      Correct answer: $$x<-3$$
      $$x>3$$
      $$x>-3$$

      Q6.
      Which inequality represents all values which satisfy both of the drawn inequalities?

      An image in a quiz
      $$4 < x \le 6$$
      $$x > 4$$
      $$x \ge 4$$
      $$x > 6$$
      Correct answer: $$x \ge 6$$

      6 Questions

      Q1.
      Which of these shows all solutions to the inequality $$19<2x+3 \le 21$$ ?

      $$7 < x \le 9$$
      Correct answer: $$8 < x \le 9$$
      $$8 < x \le 12$$
      $$9 < x \le 11$$
      $$11 < x \le 12$$

      Q2.
      Which of these shows all solutions to the inequality $$-2 < -x < 1$$ ?

      $$-2 < x < -1$$
      $$-2 < x < 1$$
      Correct answer: $$-1 < x < 2$$
      $$1 < x < 2$$

      Q3.
      Which of these represents all values which satisfy both $$x>3$$ and $$4<x$$ ?

      $$x>3$$
      $$x<4$$
      Correct answer: $$x>4$$
      $$3<x<4$$
      $$x<3$$ or $$x>4$$

      Q4.
      What are the solutions to the inequality $$x+1<3x+1<x+7$$ ?

      $$-3 < x < 0$$
      Correct answer: $$0< x < 3$$
      $$1 < x < 3$$
      $$1 < x < 6$$

      Q5.
      Which is the correct way to separate $$3x+2 \le 4x+3 \le 2x+9$$ into two inequalities to solve?

      $$3x + 2 \le 4x$$ and $$3 \le 2x + 9$$
      Correct answer: $$3x + 2 \le 4x + 3$$ and $$4x + 3 \le 2x + 9$$
      $$4x+1 \ge 3x+2$$ and $$4x+3 \ge 2x+9$$
      $$3x+2 \le 4x+3$$ and $$3x+2 \le 2x+9$$

      Q6.
      Solve the inequality $$3x+2 \le 4x+3 \le 2x+9$$.

      Correct answer: $$-1 \le x \le 3$$
      $$-1 \le x \le 6$$
      $$1 \le x \le 3$$
      $$1 \le x \le 6$$

      To help you plan your 11 maths lesson on: Solving more complicated linear inequalities, download all teaching resources for free and adapt to suit your pupils' needs...