Question

Solve the equation. $$-21 m=42$$

Short answer

The solution to the equation \(-21 m = 42\) is \( m = -2 \)

Step-by-step solution

Identify the Equation

The given equation is: \(-21 m = 42\)

Isolate the Variable

To isolate \( m \), divide both sides of the equation by \(-21\): \[m = \frac{42}{-21}\]

Simplify the Right Side

Simplify the right side to get the value of \( m \). This yields: \[m = -2\]

Key concepts

Isolate the Variable

One of the foundational skills in solving linear equations is learning how to isolate the variable. It involves rearranging the equation so that the variable you are solving for is on one side of the equation by itself. In the given exercise, where we have \( -21m = 42 \), our goal is to get \( m \) on its own. This is accomplished by performing the inverse operation to the one affecting the variable. Since \( m \) is being multiplied by -21, we therefore divide both sides of the equation by -21. This leaves us with \( m = \frac{42}{-21} \) effectively isolating \( m \) on one side.

Here, it is crucial to apply the same operation to both sides to maintain the equality. If you imagine a balance scale, whatever you do to one side must be done to the other to keep it balanced. Isolating the variable allows us to find its value without changing the meaning of the original equation.

Equation Simplification

After isolating the variable, the next step is equation simplification. Simplification makes the equation easier to understand and solve. This is where we simplify the terms and perform basic arithmetic to find the simplest form of the variable's value. In our example, once we've isolated \( m \) and have the equation \( m = \frac{42}{-21} \) the simplification is straightforward. Since 42 divided by -21 is -2, \( m = -2 \).

Equation simplification is like peeling away layers to reveal the core number that represents the variable. It's like reducing a recipe to its most basic ingredients. This clarity brings us to the solution with more ease, ensuring that the underlying mathematics is sound and the steps to solving the problem are clear.

Algebraic Operations

Algebraic operations are the tools that let us manipulate mathematical expressions. They include addition, subtraction, multiplication, and division, and they can have a profound impact on solving equations. With algebraic operations, you're essentially playing with numbers and operations to maintain the balance of an equation while trying to solve it.

Applying these operations to our example equation, the operation at play is division. We divide both sides of the equation by -21 to undo the multiplication of \( m \) by -21. This illustrates how algebraic operations can help transform equations into simpler forms, making the process of finding the value of the variable straightforward. Think of these operations like rules of a game. Understanding and correctly applying them will consistently allow you to solve similar equations correctly and with confidence.