Use the expression to complete the following tasks:

$\left(3 a^2-5 a b+b^2\right)-\left(-3 a^2+2 b^2+8 a b\right)$



What is the additive inverse of the polynomial being subtracted?

A$-3 a^2-2 b^2-8 a b$
B$-3 a^2+2 b^2-8 a b$
C$3 a^2-2 b^2-8 a b$
D$3 a^2+2 b^2+8 a b$

Verified Answer :

  • Identify the polynomial being subtracted: \(P = -3a^2 + 2b^2 + 8ab\).
  • Recall that the additive inverse \(Q\) satisfies \(P + Q = 0\), which means \(Q = -P\).
  • Distribute the negative sign to negate each term: \(Q = 3a^2 - 2b^2 - 8ab\).
  • Select the corresponding option: \(\boxed{c}\).

Explanation

  1. Identifying the Polynomial and the Goal

The problem asks for the additive inverse of the polynomial being subtracted from the expression \((3a^2 - 5ab + b^2) - (-3a^2 + 2b^2 + 8ab)\). The polynomial being subtracted is \(P = -3a^2 + 2b^2 + 8ab\). By definition, the additive inverse of a polynomial \(P\) is another polynomial \(Q\) such that \(P + Q = 0\). This implies that \(Q = -P\).

  1. Calculating the Additive Inverse

To find the additive inverse \(Q = -P\), we need to negate every term within the polynomial \(P = -3a^2 + 2b^2 + 8ab\).
Distributing the negative sign across the polynomial, we calculate:
\[Q = -(-3a^2 + 2b^2 + 8ab)\]
\[Q = -(-3a^2) - (2b^2) - (8ab)\]
\[Q = 3a^2 - 2b^2 - 8ab\]
Thus, the additive inverse is \(3a^2 - 2b^2 - 8ab\).

  1. Selecting the Correct Option

Comparing our result \(3a^2 - 2b^2 - 8ab\) with the provided options:

A\(-3a^2 - 2b^2 - 8ab\)
B\(-3a^2 + 2b^2 - 8ab\)
C\(3a^2 - 2b^2 - 8ab\)
D\(3a^2 + 2b^2 + 8ab\)

The calculated additive inverse matches option c.

Examples

The concept of additive inverses is fundamental in algebra, much like how finding the "opposite" of a number helps in balancing accounts. For example, if you have a debt of \(\$150\), which can be represented as \(-150\), the additive inverse is \(\$150\), which represents earning that amount to reach a net balance of zero. Similarly, in engineering or physics, if you define a specific force as a vector in one direction, the additive inverse represents the equal and opposite force that maintains equilibrium in the system.