Factoring trinomials

• Wiskunde
• Middelbare school
• havo
• Leerjaar 3

Factoring trinomials

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• Start (5 min)
• New subject (20 min)
• Bettermarks (20 min)
• End lesson (5 min)

Recap last lesson
13.2: Factoring binomials

Factor:

15p​2​​+10p

Factor:

10r​2​​+14r

Recap 13.2 Factoring binomials

Factor:

10r​2​​+14r

Recap 13.2 Factoring binomials

Factor:

Solve:

10r​2​​+14r

10r​2​​+14r=0

Solve:

4x​2​​+7x=0

Solve:

4x​2​​+7x=0

Find a, b and c in the formula

12x​2​​−5x+17

Note 13.3: Factoring trinomials

When factoring trinomials you are going to use the product-sum method. You need to find two numbers whose product (multiplied) is c and whose sum (added) is b.

Example: Factor

So 

x​2​​+29x+100

4⋅25=100

4+25=29

x​2​​+29x+100=(x+4)(x+25)

Factorizing trinomials

x​2​​+7x+10

Factor

x​2​​+9x+8

Factor

x​2​​+9x+8

Factor

x​2​​+19x+90

Factor

x​2​​+19x+90

Factor

x​2​​+6x−7

Factor

x​2​​+6x−7

Solving trinomials:

x​2​​+9x+20=0

Solving trinomials:

x​2​​+9x+20=0

(x+4)(x+5)=0

Solving trinomials:

        or                                                                                        

                                                                            

x​2​​+9x+20=0

(x+4)(x+5)=0

x+4=0

x+5=0

Solving trinomials:

        or                                                                                        

or                                                                                      

x​2​​+9x+20=0

(x+4)(x+5)=0

x+4=0

x+5=0

x=−4

x=−5

13.3 Factoring trinomials

Solving a trinomial using the product-sum method:

Example, solve:
Step 1: Factorize

Step 2: Make equations                                                     or
Step 3: Solve the equations                                       or

                                                                                          

x​2​​+9x+20=0

(x+4)(x+5)=0

x+4=0

x+5=0

x=−4

x=−5

Bettermarks

• Work on 13.3
  
• Until the end of the lesson
• Raise your finger if you have any questions or when you're finished
  
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