Here is a quadratic expression The coefficient of

Here is a quadratic expression: The coefficient of x is labelled b The constant value is labelled c

Discuss: Which of these expressions are quadratic expressions? How do you know?

What is the value of c in this expression? 3 2 4

What is the value of b in this expression? 3 2 4

What is the value of b in this expression? 2 -2 3

What is the value of a in this expression? 6 -2 4

What is the value of a in this expression? -1 0 1

What is the value of b in this expression? -3 2 3

What is the value of c in this expression? -3 2 3

What is the value of a in this expression? -3 2 3

Which of these expressions are quadratic equation?

This is the Quadratic Formula:

Memory Game You will have 10 seconds to look at the quadratic equation You have to try and recreate as much of it as possible after this time has passed.

The Quadratic Formula

2 x 2 + 5 x – 1 = 0 x= x= SIMPLIFY x= x= – 5 + 33 SOLVE x = 0. 186 4 –b ± b 2 – 4 ac 2 a – 5 ± 52 – (4 × 2 × – 1) SUBSTITUTE 2× 2 – 5 ± 25 + 8 4 or x= – 5 – 33 SPLIT 4 x = – 2. 686 (to 3 d. p. )

Your turn: Fill in the blanks

In your books: Solve the following to 2 decimal places. * Questions can also be solved by factorising

Mark your work (a) x = -3 and -4 (b) x = -2. 38 and -4. 62 (c) x = 12. 09 and 0. 91 (d) x = -5 and 2 (e) x = -0. 21 and 1. 21 (f) x = -0. 25 and -1 (g) x = 1 and -0. 67 (h) x = 3 and -3 (i) x = 0. 50 and x = 0 (j) x = -3. 87 and -0. 13 (k) x = -10. 20 and 10. 20 (l) x = 2 and 3

Can you spot the common mistake?

Challenge Using the digits 1 to 9, at most once each for a, b and c, find the results with the greatest and least value