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Solving Quadratics

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18

Quadratic Equations

Solving quadratic equations by factorising
Quadratic application problems.
Completing the square to solve a quadratic

Activity
Solving factorised Quadratics | Unfactorised | Harder (www.transum.org)

 

Class notes, Blank notes

Ex6.01, Ex6.02, Ex6.03, Ex6.04,

Theta pg 23

NuLake EAS Q357 - 392

 

Khan Academy Solving Quadratics by factorising

old code

 

 

Jump down to... Factorised Quadratics | Expanded Quadratics A | Expanded Quadratics B| Rearranging | Applications

Factorised Quadratics

A factorised quadratic is solved by making each bracket = 0

1) (x + 2)(x − 5) = 0

Solution

2) (x + 6)2 = 0

Solution

3) x(x − 7 )= 0

Solution

4) (2x + 5)(5 − 3x)= 0

Solution

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Summary:

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Expanded Quadratics A

An expanded quadratic must be factorised first before solving.

1) x2 + 4x + 3 = 0

   Factorise

   Solution

2) x2 − x − 6 = 0

 Factorise

 Solution

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Expanded Quadratics B

An expanded quadratic must be factorised first before solving.

3) x2 − 9x = 0

 Factorise

 Solution

4) 2x2 + 7x + 3 = 0

 Factorise

 Solution

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Summary:

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Rearranging

A quadratic equation may need to be rearranged to be '=0' before factorising and solving.

1) x2 + 3x = 18

Rearrange

 Factorise

 Solution

2) (x + 1)(x − 7) = 3x − 7

Expand

  Rearrange

   Factorise & Solution

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Summary:

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Applications

Two posters have the same area. One is square, the other rectangular.
Find the possible area(s) of one poster. (Lengths in m)

1) Form Equations

2) Expand & Simplify

3) Rearrange

4) Factorise

5) Solve

6) Answer Q

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Summary:

 

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