Question

Which expression is equivalent to 9x^5+3x(4x^4-3x^2)^2

Answer 1

D. 48x^9-72x^7+36x^5

Explanation:

Just took it. Edg 2020. Hope this helps :)

Btw Look at you doing your school work looking smart! I see youuu! (even if you are cheating a lil but its ok im doing the same xD)

Answer 2

`48x^9-72x^7+36x^5`

Explanation:

The initial expression is:

`9x^5+3x(4x^4-3x^2)^2`

First expand the squared part (inside the parenthesis):

`9x^5+3x(4x^4-3x^2)(4x^4-3x^2)\\9x^5+3x(16x^8-24x^6+9x^4)\\`

Then, multiply the terms inside the parenthesis by 3x applying the distributive property:

`9x^5+3x(16x^8-24x^6+9x^4)\\9x^5+48x^9-72x^7+27x^5`

Finally add terms with the same exponent

`48x^9-72x^7+36x^5`