Alina fully simplifies this polynomial and then writes it in standard form.

[tex]\[ xy^2 - 2x^2y + 3y^3 - 6x^2y + 4xy^2 \][/tex]

If Alina wrote the last term as [tex]\[ 3y^3 \][/tex], which must be the first term of her polynomial in standard form?

A. [tex]\[ xy^2 \][/tex]
B. [tex]\[ 5xy^2 \][/tex]
C. [tex]\[ -8x^2y \][/tex]
D. [tex]\[ -2x^2y \][/tex]



Answer :

To find which term should be the first term in Alina's polynomial when written in standard form, let's follow the step-by-step process of simplifying and combining like terms.

Here is the polynomial given:
[tex]\[ x y^2 - 2 x^2 y + 3 y^3 - 6 x^2 y + 4 x y^2 \][/tex]

### Step 1: Identify and Combine Like Terms

The polynomial consists of different terms that we can group together based on their variable components.

1. [tex]\( x y^2 \)[/tex] terms:
- [tex]\( x y^2 \)[/tex]
- [tex]\( 4 x y^2 \)[/tex]

2. [tex]\( x^2 y \)[/tex] terms:
- [tex]\( -2 x^2 y \)[/tex]
- [tex]\( -6 x^2 y \)[/tex]

3. A single [tex]\( y^3 \)[/tex] term:
- [tex]\( 3 y^3 \)[/tex]

### Step 2: Combine the Like Terms

For [tex]\( x y^2 \)[/tex] terms:
[tex]\[ x y^2 + 4 x y^2 = 5 x y^2 \][/tex]

For [tex]\( x^2 y \)[/tex] terms:
[tex]\[ -2 x^2 y - 6 x^2 y = -8 x^2 y \][/tex]

The [tex]\( y^3 \)[/tex] term remains as is:
[tex]\[ 3 y^3 \][/tex]

Thus, after combining like terms, the polynomial is:
[tex]\[ 5 x y^2 - 8 x^2 y + 3 y^3 \][/tex]

### Step 3: Write the Polynomial in Standard Form

In standard form, a polynomial is written in descending order of the exponents of the variables. The term [tex]\( 3 y^3 \)[/tex] is stated to be the last term. Thus:
[tex]\[ 3 y^3 \][/tex]

First, let's determine the highest-order term among [tex]\( 5 x y^2 \)[/tex] and [tex]\( -8 x^2 y \)[/tex]:

- [tex]\( x^2 y \)[/tex] has a higher degree (sum of exponents is 3: [tex]\( 2 + 1 \)[/tex]).
- [tex]\( x y^2 \)[/tex] has a lower degree (sum of exponents 3: [tex]\( 1 + 2 \)[/tex]).

When comparing by traditional priority, prioritize the term with higher degree in one variable, and in this case, the order of terms favor [tex]\( x^2 \)[/tex] terms.

So we arrange the terms in standard form:
[tex]\[ -8 x^2 y + 5 x y^2 + 3 y^3 \][/tex]

Thus, the first term in standard form is:
[tex]\[ \boxed{-8 x^2 y} \][/tex]