Single Polynomial in Standard Form

[white shale]

does 125x^9 + 9 work too or

idk

[echo crow]

The square of (a+b) equals the square of a + square of b + 2ab. In fact, there is also a formula for the cube of (a+b). If you don't remember it, you can expand it as (a+b)(a+b)(a+b) to calculate.

[white shale]

I ended up getting 125x^3 + 150x^2 + 165x + 72

I did (5x+3)(5x+3)(5x+3)

However, apparently the correct answer is 125x^3 + 225x^2 + 135x + 27 on Google.

@echo crow Do you know what I am doing wrong or if I am.

I may have miss-calculated.

I'm going over it again.

[echo crow]

you could square (a+b) to expand it as (a^2+2ab+b^2). You can write the cube of (a+b) as (a^2+2ab+b^2)(a+b), then multiply each term separately, and simplify it further

[white shale]

i got 125x power of 3 + 75 x squared + 75x squared + 45x. but then the last bracket multiply by 3

It ruins my answer.

(5x+3)(5x+3)(5x+3). the last bracket I have to multiply 5x by everything I have, and then 3 by eveyrhting I have right

or do I just alternate

I'm confusing myself now.

[echo crow]

(25x^2+9+30x)(5x+3) = 125x^3+75x^2+45x+27+150x^2+90x

25x^2 multiply 5x=125x^3 ，25x^2 multiply 3=75x^2，9multiply 5x=45x，9 multiply3=27，30x multiply 5x=150x^2,30x multiply 3=90x,

Is this clear now？😺