# Thread: FACTORING TRINOMIALs

1. ## FACTORING TRINOMIALs

25a2 +9b2 + 30ab

2x2 - 16x + 32

5c2 +30c + 45

128x2 +96xy + 18y2

450a2 +242c2 + 660ac

y2 - xy - 56x2

Can you show me how to do these promblems. I realy what to now how to learn to do theses problems.

2. Originally Posted by frow4
25a2 +9b2 + 30ab

2x2 - 16x + 32

5c2 +30c + 45

128x2 +96xy + 18y2

450a2 +242c2 + 660ac

y2 - xy - 56x2

Can you show me how to do these promblems. I realy what to now how to learn to do theses problems.
We did a bunch for you this afternoon. Can you please show us some of your work now? What have you tried?

3. i can do simple ones like

x2n + 10xn + 16

(x^n + 8)(X^n+2)

y2x - yx - 20

(y^x-5) (y^x-4)

what i am having troubles on

128x2 +96xy + 18y2 ; 450a2 +242c2 + 660ac

because of the x^2 and Y^2 and xy I have no idea what to do with those powers

4. Originally Posted by frow4
y2 - xy - 56x2
I'll do this one for you.

The coefficient of $y^2$ is 1.

So we can say this:

$y^2 - xy - 56x^2 = (y + \text{something})(y - \text{something})$

Now take a look at 56. We want factors of 56 so that the difference of the two factors gives us -1

7 and 8 clearly satisfies this condition.

So the final answer is:

$y^2 - xy - 56x^2 = (y + 7x)(y - 8x)$

5. Originally Posted by frow4

128x2 +96xy + 18y2

So You times 128 by 18 to get 2304. factors of 2304 That equals 96 is 48.

So it (128x+48y)^2

then you reduces it to
(8x+3y)^2

Is that right

6. Originally Posted by frow4
So You times 128 by 18 to get 2304. factors of 2304
Why are you doing this?

128x2 +96xy + 18y2

First factor out a 2.

$= 2(64x^2 + 48xy + 9y^2)$

$= 2(8x + 3y)(8x + 3y)$

$= 2(8x + 3y)^2$

7. Originally Posted by Soroban
.

Example: $6x^2 - 35x + 36$

Write the two pairs of parentheses and "split the x's": . $(\;x\qquad)(\:x\qquad)$

Use the first coefficient twice: . $(\overbrace{6x}^\downarrow\qquad)(\overbrace{6x}^\ downarrow\qquad)$

Multiply the first coefficient by the last coefficient: . $6 \times 36 \,=\,216$

We will factor $216$ into two parts.
Note the sign of the last term.
. . If "+", think sum.
. . If "-", think difference.
i look this up and it tells me to do it