Question

Choose the correct simplification of
9x2(4x + 2x2 – 1)

EXPLAIN HOW TO DO IT??!?!??!??!?!??!

Answer 1

well in my book, simplification is factoring...however, some say simplifying means expanding...so how were you taught?

Answer 2

well here let me show you these are the answers

A: 18x4 + 36x3 − 9x2

B: 18x4 − 36x3 + 9x2

C : 36x4 + 18x3 − 9x2

D: 36x4 − 13x3 + 9x2

So what do you think would get us here?

Answer 3

ahh so you expand then

Answer 4

just distribute 9x^2 into 4x + 2x^2 - 1

you know how right?

Answer 5

yes multiply right?

Answer 6

9x^2 * 4x = 36x^3
9x^2 * 2x^2 = 18x^4
9x^2 * -1 = - 9x^2

Answer 7

right?

Answer 8

what you wrote are right...now add those

Answer 9

add them ?? why??

Answer 10

well....because that's distributive property..


2x (3x + 1)

2x * 3x = 6x^2

2x * 1 = 2x

add them

6x^2 + 2x

forgot?

Answer 11

so is that answer?

Answer 12

1) look at the problem i wrote

2) does that answer resemble any of your choices?

Answer 13

nooo???

Answer 14

like i said.. what you wrote is right already. just add them together to get the final answer

Answer 15

but it says its wrong on the test ? :?

Answer 16

normally you would arrange the powers of x in a descending order. From your results you would start with:\[18x ^{4}\]

Answer 17

Then follow with:\[18x ^{4}+36x ^{3}\] and so on.

Answer 18

Did you say choice Choice A. was wrong?