Math Problem Statement

Combine like terms in the given polynomial. Then, evaluate for x = 4, y = -2. xy - 2xy + 3x²y - 4xy² + 2xy²

Solution

The given expression is:

xy2xy+3x2y4xy2+2xy2xy - 2xy + 3x^2y - 4xy^2 + 2xy^2

Step 1: Combine Like Terms

We can group the terms that are similar:

xy2xy=xyxy - 2xy = -xy 4xy2+2xy2=2xy2-4xy^2 + 2xy^2 = -2xy^2

Thus, the simplified polynomial becomes:

xy+3x2y2xy2-xy + 3x^2y - 2xy^2

Step 2: Substitute x=4x = 4 and y=2y = -2

Now we substitute the values x=4x = 4 and y=2y = -2 into the simplified expression:

xy=(4)(2)=8-xy = -(4)(-2) = 8 3x2y=3(42)(2)=3(16)(2)=963x^2y = 3(4^2)(-2) = 3(16)(-2) = -96 2xy2=2(4)(22)=2(4)(4)=32-2xy^2 = -2(4)(-2^2) = -2(4)(4) = -32

Step 3: Add the Results

Now, sum up the terms:

8+(96)+(32)=89632=1208 + (-96) + (-32) = 8 - 96 - 32 = -120

So the correct answer is: xy2xy2+3x2y;120\boxed{-xy - 2xy^2 + 3x^2y; -120}

The correct option matches the second choice.

Would you like more details or have any further questions?


Here are 5 related questions for practice:

  1. How do you identify like terms in a polynomial?
  2. What happens when you substitute negative values into polynomial expressions?
  3. How do exponents affect the calculation when substituting values into a polynomial?
  4. How can you quickly simplify polynomials with multiple like terms?
  5. How does factoring polynomials relate to combining like terms?

Tip: Always simplify expressions before substituting values to avoid unnecessary complications.

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Math Problem Analysis

Mathematical Concepts

Polynomial simplification
Substitution

Formulas

Combining like terms
Substitution for variables

Theorems

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Suitable Grade Level

Grades 8-10