2TH §11.5 Quadratic equations

• Wiskunde
• Middelbare school
• havo, vwo
• Leerjaar 2

§11.5 Quadratic equations

In this LessonUp .....

All that you have learnt up till now is repeated.

To help you doing the exercises from §11.5

Solving quadratic equations

You know two methods of solving quadratic equations:

- Cards:

- Factorising:  A x B = 0, then A = 0 or B = 0

When to use which method?

A. Solving quadratic equations with CARDS

Question 1:  Can you use cards?

(You can use cards if the equation contains only 1 variable)

Yes? Solve using cards.

No? Go to B,  for Factorising Binomials and Trinomials

A. Solving quadratic equations with cards

Use the balance method (add/subtract the same amount, divide/multiply by the same number , take the square root on both sides of the equal sign, don't forget the second solution)

B. Solving quadratic equations

by Factorising

Question 2: Is one side of the equation equal to 0?

Yes?  

See examples next slide. We only factorise,

soon we'll solve it too!

No? Reduce to zero

Factorise binomial

Find the largest common factor and place in front of a set of single brackets, fill in the remaining factors inside the brackets.

(See §11.2). Note: the 3rd example has to be made equal to 0 first!

Reduce to zero

Use the balance method (add/subtract the same term on both sides of the equal sign).

Factorise trinomial

Find two numbers that have the number in front of x as a sum and the single numbers as a product. Write as (x + ...)(x + ...).

(See §11.3)

Solving quadratic equation

4. Use the rule: if A x B = 0, then A = 0 or B =0

Next come some examples of 

Factorising Binomials and Trinomials.

A x B = 0

A x B = 0

Let's do together

Homework

Do §11.5 exercises 38, S39, 41