Question 1 Easy2 marks
Solve x2-4>0.
Show answer
Answer: x<-2 or x>2
- Same boundaries -2 and 2.
- The square exceeds 4 outside them.
- Method (1): Same boundaries -2 and 2
- Accuracy (1): Answer x<-2 or x>2
Paper Together: sit a paper in a room with your friends.See how it works
Here you practise quadratic inequalities; the teaching is elsewhere. Below are 4 questions (2 warm-up, 2 core, 0 stretch, 1 to 2 marks each), all new to you if you read the topic page. Also here: a multi-part show-that question, 15 quick checks. If a question beats you, go back to the Quadratic inequalities topic page or the Quadratic inequalities worked examples.
How to use this page: Try the stretch set first; if you drop marks, come back down to core and find which step went wrong.
2 questions, 1 to 2 marks each. Leading off: “Solve x2-4>0.”
Solve x2-4>0.
Answer: x<-2 or x>2
Solve (x+1)(x-3)<0.
Answer: -1<x<3
2 questions, 1 to 2 marks each. Opening with: “Solve x2+2x-3>0.”
Solve x2+2x-3>0.
Answer: x<-3 or x>1
Solve x2+2x-3<=0.
Answer: -3<=x<=1
Exam style: 2 linked parts worth 3 marks in total. Set by Yumio in the GCSE question style.
Part (a) is a show that question: the answer is printed and the method earns the marks. Show your working throughout.
(a) The inequality x2>9 has which solution? Show that the answer is x<-3 or x>3. [2 marks]
(b) Solve (x-1)(x-4)<=0 and say whether 1 is included. [1 mark]
Answer: Shown: the working reaches x<-3 or x>3
Marks for this part:
Answer: 1<=x<=4
Marks for this part:
Short one-step questions. Pick an option before you open the answer.
Where is a positive parabola negative?
Between its two roots. Between its two roots.
Where is a positive parabola positive?
Outside its two roots. Outside its two roots.
What is the difference between x2-5x+6<0 and x2-5x+6=0?
The equation gives the boundaries. The inequality gives a region. The equation gives the boundaries. The inequality gives a region.
Does a strict inequality include the roots?
No. The roots make the expression zero, not negative or positive. No. The roots make the expression zero, not negative or positive.
When does the solution include the roots?
When the sign is less than or equal, or greater than or equal. When the sign is less than or equal, or greater than or equal.
Why can you divide 2x2-8x+6<0 by 2?
2 is positive, so the inequality sign stays the same. 2 is positive, so the inequality sign stays the same.
What would a negative divisor do to the sign?
It would flip the inequality. Dividing by a negative is a different step. It would flip the inequality. Dividing by a negative is a different step.
How do you write an outside region?
Two inequalities joined by or. Two inequalities joined by or.
How do you write an inside region?
One double inequality, smaller root, then x, then larger root. One double inequality, smaller root, then x, then larger root.
The roots are -2 and 2 and the curve is above the axis outside. Which inequality is that for y=x2-4?
x<-2 or x>2. x<-2 or x>2.
Why sketch the U-shape?
It shows inside versus outside without testing lots of numbers. It shows inside versus outside without testing lots of numbers.
A test point x=0 in x2-5x+6 gives +6. What does that say?
Zero is not in the less-than region. The region is between 2 and 3. Zero is not in the less-than region. The region is between 2 and 3.
Can a quadratic inequality have one root only as its solution?
Only in special cases, such as a square that is never negative. The usual two-root case has an interval or two rays. Only in special cases, such as a square that is never negative. The usual two-root case has an interval or two rays.
(x-2)(x-3)<0 is true for which kind of x?
x between 2 and 3. x between 2 and 3.
Name the solution of x2-4<0.
-2<x<2. The square is less than 4 between -2 and 2. -2<x<2. The square is less than 4 between -2 and 2.
AQA-style and Edexcel-style questions. Yumio is not affiliated with, endorsed by or connected to AQA, Pearson Edexcel or any other exam board.