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3x^2+6xy+3y^2factor completely

User Cooow
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1 Answer

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So we must factor the following expression:


3x^2+6xy+3y^2

First of all is important to notice that all terms are multiplied by an integer that is a multiple of 3. Then 3 is a common factor and we can re-write the expression like this:


3x^2+6xy+3y^2=3\cdot(x^2+2xy+y^2)

Now let's have a look at the expression inside parenthesis but first let's recall the expression for the square of a binomial. For two real numbers a and b we get:


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

If you replace a and b with x and y we get the following:


a^2+2ab+b^2\rightarrow x^2+2xy+y^2

Which means that:


x^2+2xy+y^2=(x+y)^2

Then the factored form of the original expression and answer to this problem is:


3(x+y)^2

User Sakhri Houssem
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