Math Problem Statement

Solve the system of equations: x - 2y = 9 and y = x - 3.

Solution

The system of equations shown in the image is:

x - 2y = 9 \\ y = x - 3 \end{cases}$$ To solve this system of equations, we can use substitution. Here's the step-by-step solution: 1. From the second equation, $$y = x - 3$$. 2. Substitute this expression for $$y$$ into the first equation: $$x - 2(x - 3) = 9$$ 3. Simplify the equation: $$x - 2x + 6 = 9$$ $$-x + 6 = 9$$ 4. Solve for $$x$$: $$-x = 9 - 6$$ $$-x = 3 \quad \Rightarrow \quad x = -3$$ 5. Now substitute $$x = -3$$ back into the second equation to find $$y$$: $$y = -3 - 3 = -6$$ So, the solution to the system is $$x = -3$$ and $$y = -6$$. Let me know if you'd like more details or have any questions! --- Here are 5 related questions to explore: 1. What is the graphical interpretation of this system of equations? 2. How would you solve the system using the elimination method? 3. What happens if we change the second equation to $$y = x + 3$$? 4. How do we determine if a system of linear equations has no solution or infinitely many solutions? 5. How would the solution change if the coefficient of $$y$$ in the first equation was different? **Tip:** In systems of equations, substitution is useful when one equation is already solved for one variable!

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Systems of Equations
Substitution Method

Formulas

Substitution Method for solving systems of equations

Theorems

Properties of linear equations

Suitable Grade Level

Grades 8-10