Question

What is the product of the polynomials . (8x^2+7x+9)(7x^3+9x)

Answer 1

distribute the equations? have you done this before

Answer 2

Is it 56x^5+49x^4+135x^3+81x?

Answer 3

http://prntscr.com/1en788

Answer 4

It only shows that.

Answer 5

Yoda, is your final answer, 56x^5+49x^4+135x^3+81x ?

Answer 6

Yes.

Answer 7

@yoda5657
Your first response is not correct.

Answer 8

Hmm.

Answer 9

no thats not correct, try adding the like terms

Answer 10

56x^5+49x^4+135x^3+63x^2+81x?

Answer 11

I thought 56x^5+49x^4+135x^3+81x was the correct answer choices.

Answer 12

@yoda5657
The first step must always have a number of terms that is equal to the number of the terms of the two polynomials multiplied together.
You are multiplying a 3-term polynomial by a 2-term polynomial. The first step of all the multiplications has to have 3 x 2 = 6 terms.

Answer 13

The x^2 term is missing from
56x^5+49x^4+135x^3+81x

Answer 14

63^2?

Answer 15

63x^2?

Answer 16

yes

Answer 17

56x^5+49x^4+135x^3+63x^2+81x

Answer 18

Correct

Answer 19

(8x^2+7x+9)(7x^3+9x)

8x^2 * 7x^3 = 56x^5
8x^2 * 9x = 72x^3

7x * 7x^3 = 49x^4
7x * 9x = 63x^2

9 * 7x^3 = 63x^3
9 * 9x = 81x

Now you would have:
56x^5 + 72x^3 + 49x^4 + 63x^2 + 63x^3 + 81x

You can comine 72x^3 and 63x^3 because the exponent are the same.
72x^3 + 63x^3 = 135x^3

Now you would have: 56x^5 + 39x^4 + 135x^3 + 63x^2 + 81x.

Ouch, my bad.

Answer 20

You have to distribute every term on the left to every term on the right and then combine like terms.

8x^2 has to go to 7x^3 and 9x
7x has to go to 7x^3 and 9x
9 has to go to 7x^3 and 9x.

This making the answer 56x^5+49x^4+135x^3+63x^2+81x.

Good job @yoda5657