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Multiplying Polynomials

The world is open to you.

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Why its important for algebra

• For geometry and finding the area of an object.

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What is a polynomial ???

• Definition: a polynomial is two numbers or variables being added together

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How to?The foil method

•To multiply two binomials use the FOIL method.  

•    F    the product of the First two terms

•    O   the product of the Outside terms

•    I    the product of the Inside terms

•    L    the product of the Last terms

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•( a + b )( c + d ) = ?•then•    F--- ac•    O--- ad•    I--- bc•    L--- bd •Then add as normal. Then, •combine like terms (if

possible). • (It should end up as ax + bx +c)

So if……………….

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Example.

• (x+2)(x+4)

• F:X*X=x2

• O:X*4=4x

• I:2*x=2x

• L:2*4=8

• X2+4x+2x+8= X2+6x+8

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Multiplying using the plummet

• Arrange each number at one of the sides of the square

• Multiply ac, • ad bc ad• Add as• normally. • Then, combine • like terms • (if possible). • (It should end up as ax + bx +c)

A B

C

D

AC CB

DA DB

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Example

• (x+2) (x+3)

• Insert numbers

• x2+2x+3x+6

• = x2+5x+6

X 2

X x2 2x

3 3x 6

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When will you ever use this in your life?

• If you become a math teacher (duh)

• When helping a sibling, cousin, kid your baby sitting, with homework

• If you became a artist, or in a business situation.

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Real life example.

• Say you needed to no the area of a field. the with was represented by (x+2) and the with by (x+3) as we know you multiply to find the area. So…Ill use the foil method.

• X*x=x2

• X*2=2x• 3*x=3x• 3*2=6• Combine like terms• X2+5x+6

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Another real life example

• If you were a painter and you got a easel that was (x+5) by (x+5) an you needed one to be bigger then x2 +7x+15, would it work.

• x*x=x x2

• X*5=5x• 5*x=5x• 5*5=25• X x2 +10x+25• So your answer is YES!