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Pre alg. I'm feeling pretty dumb about now.

  1. Oct 2, 2006 #1
    first off the question I'm stuck on is..

    2(3.2) + 2(6.4)=

    Factor by using the distributive law of real numbers in reverse.

    For the life of my this is just not clicking. It's either too late or I'm incapable. ugh!
    I went back and read the part on reverse distributive properties, it says, " The reverse of the distributive property is called factoring. The following are some examples."

    4(3) + 4(2)= 4(3+2) - the real number factor, 4 is called the common factor of the addends.

    I'm thinking I probably need to drag out my book from my last math class and look up factoring. This should be on the homework help page..but they didn't have a section for lowly pre algebra
    :redface:
     
  2. jcsd
  3. Oct 2, 2006 #2

    HallsofIvy

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    The distributive law says a(b+ c)= ab+ ac. In other words, adding b and c first and then multiplying by a is the same as first multiply each by a and then adding. In your 4(3) + 4(2)= 4(3+2), 4 plays the part of "a" above. Since there is a "4" in each part of the sum, it can be "taken out" as a factor.

    Now go back to "2(3.2) + 2(6.4)= ". Do you see that 2 multiplying each of 3.2 and 6.4? That's ab+ ac with a= 2, b= 3.2 and c= 6.4. And it is equal to a(b+ c). What is that in terms of your numbers?
     
  4. Oct 2, 2006 #3
    thanks

    I've got it now. How they got four was throwing me. It just didn't click that they were factors as they sat.. I kept looking for common factors among the factors, haha... go fig'r
     
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