# Thread: Polynomials in Standard Form

1. ## Polynomials in Standard Form

Write each function in standard form:
1. y = (x + 7)(5x + 2)(x - 6)²

I got the answer, but I am not sure if its right. Because I did it two different ways and got two different answers.

First way, I foiled (x + 7) and (5x + 2), and then foiled (x - 6) and (x - 6). Then I just multiplied the product I got.

Second way, I foiled (x - 6) and (x - 6), then multiplied the product with (5x + 2) and again, I multiplied the product of that with (x + 7).
Using the first method, the one I think is right, I got:
$5x^4 - 23x^3 - 250x^2 - 168x + 1836$

Is it right??

2. $(x + 7)(5x + 2)(x - 6)^2$
$(x + 7)(5x + 2)(x^2 -12x +36)$
$(5x^2 + 37x +14)(x^2 -12x +36)$
$(5x^2 + 37x +14)(x^2 -12x +36)$
$(5x^4 -23x^3 -250x^2 +1164x +504)$ I hope

3. Originally Posted by Power
Write each function in standard form:
1. y = (x + 7)(5x + 2)(x - 6)²

Using the first method, the one I think is right, I got:
$5x^4 - 23x^3 - 250x^2 - 168x + 1836$

Is it right??
Using a long but visible method:
$y = (x + 7)(5x + 2)(x - 6)^2$
$y = (x + 7)(5x + 2)(x^2 - 6x - 6x +36)$
$y = (x + 7)(5x + 2)(x^2 - 12x + 36)$
$y = (x + 7)(5x^3 - 60x^2 + 180x + 2x^2 - 24x + 72)$
$y = (x + 7)(5x^3 - 58x^2 + 156x + 72)$
$y = (5x^4 - 58x^3 + 156x^2 + 72x + 35x^3 - 406x^2 + 1092x + 504)$
$y = 5x^4 - 23x^3 - 250^2 + 1164x + 504$?

Different answer to yours. A third person may be able to confirm but I think mine may be right.

EDIT: Bobak beat me. He's correct.

4. Sadly, my arithmetic is very very weak!!!