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Question 1,2, and 3 how do i factor those? Can you show the work and explain how?

Question 1,2, and 3 how do i factor those? Can you show the work and explain how?-example-1
User Rclakmal
by
4.5k points

1 Answer

6 votes

1:
3n^(2)+9n+6

notice that each part is divisible by 3


3n^(2) ÷ 3 =
n^(2)

9n ÷ 3 = 3n

6 ÷ 3 = 2

so it becomes
3(n^(2) +3n+2)

3n can be rewritten as 2n+n

-you want to rewrite it into two numbers that multiply to the number that's alone (in this case 2)

which would get you


3(n^(2) +2n+n+2)

Now that it's rewritten, you can factor out n + 2 from the equation.

the answer is

3(n+2)(n+1)

And you can check that by multiplying (n+2)(n+1) which is
n^(2) +2n+n+2 and then each of those by 3, which is
3n^(2) +6n+3n+6 or
3n^(2)+9n+6, our origional equation

2:
28+x^(2) -11x

So I rewrote this as
x^(2) -11x+28 (it's the same thing, just reordered using the commutative property)

now -11x can be rewritten as -4x-7x

(remember, the two numbers should multiply to equal 28, which is our constant.)


x^(2) -4x-7x+28

now we can factor out x from the first expression and -7 from the second


x(x-4)-7(x-4)

and lastly you factor out x-4,

which would give you

(x-4)(x-7)

Make sure to check your work and make sure it multiplies to
x^(2) -11x+28

3:
9x^(2) -12x+4

The first thing I notice when looking at this problem is that both 9 and 4 are perfect squares. Not only that, but they are the squares of 2 and 3, which are products of -12

So if you rewrite 9 as
3^(2) and 4 as
2^(2), the equation becomes


3^(2) x^(2) -12x+2^(2)

now that
3^(2) x^(2) is ugly so it can be turned into
(3x)^(2)

and -12x can be rewritten as
-2*3x*2

so our equation now looks like
(3x)^2-2*3x*2+2^(2)

There's a rule that says
a^(2) -2ab+b^(2) = (a-b)^(2)

In our case, a=3x and b=2

so the final answer is


(3x-2)^2

User Fyodor Volchyok
by
4.5k points