1. ## simplifying multiplied trinomials

I can multiply this easily-but the problem says to simplify it. I have the answer and NO idea how to get there. Can someone help to simplify:

(3x^2-2x^2-7)(8x^2-8x+7)

2. Originally Posted by ab27834
I can multiply this easily-but the problem says to simplify it. I have the answer and NO idea how to get there. Can someone help to simplify:

(3x^2-2x^2-7)(8x^2-8x+7)

Multiply it. and then, look for like terms and simplify.

3. did. doesn't match what the book says the answer is. i've gotten several people to look at it; they all come back with what I did. The book says the answer is 3x^3-10x^2+8x+11. I'm completely lost how that is.

4. Originally Posted by ab27834
did. doesn't match what the book says the answer is. i've gotten several people to look at it; they all come back with what I did. The book says the answer is 3x^3-10x^2+8x+11. I'm completely lost how that is.
Are you sure you typed it right? Is it $(3x^2-2x-7)(8x^2-8x+7)$ or $(3x^3-2x^2-7)(8x^2-8x+7)\;\;?$

Is this $(3x^2-2x^2-7)(8x^2-8x+7)$ the right question in your book? If it is then

$= (3x^2-2x^2-7)(8x^2-8x+7)$

$=(x^2-7)(8x^2-8x+7)$

$=8x^4-8x^3+7x^2-56x^2+56x-49$

$=8x^4-8x^3-49x^2+56x-49$ is the simplified answer.