Question

Simplify by combining like terms. $$-9 x^{2}+9 x^{2}$$

Short answer

Question: Simplify the expression $$-9x^2 + 9x^2$$ by combining like terms. Answer: The simplified expression is $$0$$.

Step-by-step solution

Identify like terms

Since both terms are x squared terms (\(-9x^2\) and \(9x^2\)), we can combine them.

Combine the like terms

To combine the terms, we simply add their coefficients together: $$-9 + 9 = 0$$.

Write the simplified expression

Since the combined coefficient is 0, the simplified expression is: $$0x^2$$ which simplifies to just $$0$$, since any number multiplied by 0 is 0.

Key concepts

Simplification

Simplification in mathematics often involves making expressions easier to read or solve. For instance, when dealing with polynomials or algebraic expressions, one common simplification step is to combine like terms.

Combining like terms means merging terms that have the same variables raised to the same powers. In the exercise we are discussing, the like terms are \(-9x^2\) and \(+9x^2\). Since they both contain the variable term \(x^2\), we can add or subtract them.

This process simplifies expression as much as possible, eliminating unnecessary complexity by reducing the terms to their simplest form. In this specific case, combining the terms results in a zero because \(-9 + 9 = 0\). Therefore, the expression simplifies completely to 0, showing how simplification can help to reach clear and concise results.

Coefficients

Coefficients are numbers that multiply the variable(s) in an expression. In the context of our exercise, the coefficients are the numerical parts in front of the variable \(x^2\).

In \(-9x^2\), the coefficient is -9, meaning each \(x^2\) is multiplied by -9. Similarly, in \(+9x^2\), the coefficient is 9.

When combining like terms, we focus chiefly on these coefficients. In our example problem, bear in mind:

• The variable term remains unchanged; it is just the coefficients that are added or subtracted.
• Like terms share the same variable and degree, hence only the coefficients are subject to arithmetic operations

Understanding coefficients makes it simpler to handle algebraic expressions by pinpointing which parts of an expression change during operations and which stay the same.

Polynomial

A polynomial is an algebraic expression made up of terms that consist of variables, numbers, and exponents combined using addition, subtraction, and sometimes multiplication. Each term is either a constant or the product of a constant and one or more variables with non-negative integer exponents.

In our exercise, \(-9x^2 + 9x^2\) is a polynomial composed of two terms. Each term consists of a coefficient and a variable raised to the power of 2.

Polynomials can range from simple to highly complex, depending on the number of terms and degree (the highest exponent in the expression). Some key points on polynomials include:

• They can have a single variable or multiple variables.
• The degree of a polynomial is crucial for determining its shape and expectations.
• Like terms within a polynomial can often be combined for simplification.

The simplification process aids in dealing with polynomials more easily, focusing computations on their essential parts.