• GreyBeard@lemmy.one
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    5 days ago

    For those of you who were confused even after reading the comments: (a)(b) basically means a*b. My mind just didn’t connect that to the fact that (x-x)=0. in the (a-x)(b-x) stuff is also (x-x) which = 0, and anything * 0 = 0, so no matter the value of literally everything else in the equation, it all equals out to 0 because every single () will get multiplied by (x-x), which is 0. There, hopefully that will clear it up for anyone remaining lost. And like all good jokes, they are always best when you have to explain them.

    • MonkderVierte
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      4 days ago

      (a)(b) basically means a*b

      Ok, wtf. Why write it like this then?

      • superkret@feddit.org
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        4 days ago

        To make sure what’s inside the brackets is resolved internally before they’re multiplied with each other.

         (a)  (b)   =   a * b  
        (a+1)(b+1) =/= a+1*b+1
        
        • brbposting@sh.itjust.works
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          4 days ago

          TIL this notation makes it math the text up

          (a)  (b)   =   a * b  
              (a+1)(b+1) =/= a+1*b+1
          

          Edit: hmm, already shows in a code block so adding backticks didn’t do anything

      • GreyBeard@lemmy.one
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        4 days ago

        To expand on what superkret said, in math there is the concept of “order of operations”. That is to say, every function in math (add, multiply, divide) has to be done in a specific order. Since multiplication comes before addition and subtraction, if you have a formula like a-x*b-x, you will do x*b first, then a minus the result of x*b, which would give a very different result than if you did a-x and multiplied that by b-x. This is where the parenthesis come in. You are basically saying, resolve every section in parenthesis first using the proper order, then resolve the rest.

        My original example (a)(b) was over simplified, because there is no conflict there. You can also do things like (a*x)-(b*x). If there is no operator though, it is assumed multiplication, and I’m unsure why that is.

        • starman2112@sh.itjust.works
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          4 days ago

          Putting multiple asterisks in a comment makes it look italicized, at least on some Lemmy clients. If you want to have asterisks with *unitalicized* text, you gotta put a \ behind the * to negate the change

      • Jyek@sh.itjust.works
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        4 days ago

        Because you wrote a lot less when writing it this way. Groups of terms beside each other are multiplying each other and you have to solve what’s inside of those groups before multiplying them together.