how??? grade 8 algebra | Mathematics | Page 1

obsidian cave Oct 27, 2022, 4:07 PM

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Because they develop the square

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Notice that $(3x + 7)^2 = (3x + 7)(3x + 7) = 3x\cdot 3x + 3x \cdot 7 + 7\cdot 3x + 7\cdot 7) = 3^2x^2 + 21x + 21x + 7^2 = 9x^2 + 42x + 49$

sage kelpBOT Oct 27, 2022, 4:08 PM

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RFish

obsidian cave Oct 27, 2022, 4:08 PM

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So that's where the 42x comes from

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And remember that this reasoning is in summary the following formula: Let $a,b$ be numbers, then

$(a + b)^2 = a^2 + 2ab + b^2$

sage kelpBOT Oct 27, 2022, 4:09 PM

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RFish

obsidian cave Oct 27, 2022, 4:10 PM

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Don't worry

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The thing is to learn

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Well, I think it works by answering to one of my messages and saying "thanks"

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Or maybe in the general chat

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btw, now that you are with this problem

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I think you could try to learn more identities

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Write them down

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Yes

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Yes

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Okay

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There's a page on Wikipedia where they list a lot of identities like those

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Like one for (a+b)³ or even one for (a + b)ⁿ, called the Newton binomial

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Well, it depends on how much do you want to advance in math

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If you would like to study more advanced things when you finish the secondary school, then yes

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If you will be fine with the things they will teach you at school because you plan to study another thing, then it's optional

#how??? grade 8 algebra