Math Problem Statement

Solve the system of equations: x + 2y = 4, 4x + 5y = 7

Solution

To solve the system of equations:

x + 2y &= 4 \\ 4x + 5y &= 7 \end{aligned}$$ ### Step 1: Solve one equation for one variable From the first equation $$x + 2y = 4$$, solve for $$x$$: $$x = 4 - 2y$$ ### Step 2: Substitute into the second equation Substitute $$x = 4 - 2y$$ into the second equation $$4x + 5y = 7$$: $$4(4 - 2y) + 5y = 7$$ Simplify: $$16 - 8y + 5y = 7$$ $$16 - 3y = 7$$ Solve for $$y$$: $$-3y = 7 - 16$$ $$-3y = -9$$ $$y = 3$$ ### Step 3: Substitute $$y = 3$$ back into the first equation Substitute $$y = 3$$ into $$x = 4 - 2y$$: $$x = 4 - 2(3)$$ $$x = 4 - 6$$ $$x = -2$$ ### Solution: $$x = -2, \quad y = 3$$ Let me know if you want further details or explanations. Here are some related questions: 1. What method would you use to solve a system with three equations? 2. Can the substitution method always be used for nonlinear systems? 3. How can you check if a system of equations has no solution or infinite solutions? 4. What are the advantages of using elimination over substitution? 5. How would you graphically represent this system of equations? **Tip**: Always check your solution by substituting both values back into the original equations to ensure they satisfy both.

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Linear Equations

Formulas

Substitution Method
Linear Equation

Theorems

Solution of a System of Equations

Suitable Grade Level

Grades 8-10