What is the difference of the polynomials?



$\left(12 x^2-11 y^2-13 x\right)-\left(5 x^2-14 y^2-9 x\right)$


A$7 x^2+3 y^2-4 x$
B$7 x^2-3 y^2-4 x$
C$7 x^2-25 y^2-22 x$
D$17 x^2-25 y^2-22 x$

Verified Answer :

  • Distribute the negative sign to the second polynomial: \(-(5x^2 - 14y^2 - 9x) = -5x^2 + 14y^2 + 9x\).
  • Group like terms: \((12x^2 - 5x^2) + (-11y^2 + 14y^2) + (-13x + 9x)\).
  • Perform the subtraction and addition for each coefficient: \(7x^2 + 3y^2 - 4x\).
  • The final answer is \(\boxed{7x^2 + 3y^2 - 4x}\).

Explanation

  1. Simplifying the Expression

To find the difference between the two polynomials \((12x^2 - 11y^2 - 13x)\) and \((5x^2 - 14y^2 - 9x)\), we need to subtract the second polynomial from the first. This is expressed as:
\[(12x^2 - 11y^2 - 13x) - (5x^2 - 14y^2 - 9x)\]
The first step is to distribute the negative sign across the second polynomial. This changes the sign of each term within the parentheses:
\[12x^2 - 11y^2 - 13x - 5x^2 + 14y^2 + 9x\]
Now, we group the like terms (terms with the same variable and exponent) together:
\[(12x^2 - 5x^2) + (-11y^2 + 14y^2) + (-13x + 9x)\]
Finally, we perform the arithmetic for each group of like terms:

  • For the \(x^2\) terms: \(12 - 5 = 7\), so we have \(7x^2\).
  • For the \(y^2\) terms: \(-11 + 14 = 3\), so we have \(3y^2\).
  • For the \(x\) terms: \(-13 + 9 = -4\), so we have \(-4x\).

Combining these results, the simplified expression is \(7x^2 + 3y^2 - 4x\).

Examples

In everyday life, this process of combining like terms is used in budgeting and inventory management. For example, if you are calculating your total expenses after a refund, you might subtract the refunded items from your initial list of costs. Just like combining \(x^2\) terms with other \(x^2\) terms, you add or subtract the same types of costs (e.g., groceries, fuel, or rent) to find the net total, ensuring accuracy in your financial records.