Math Problem Statement

Solve the system of equations: 2a + b + 3c = 5 5a + 2b + 8c = 8 a + b + c = 8

Solution

The system of equations given in the image is:

2a + b + 3c = 5 \\ 5a + 2b + 8c = 8 \\ a + b + c = 8 \end{cases}$$ To solve for $$a$$, $$b$$, and $$c$$, we can use the elimination or substitution method. Here’s the step-by-step solution: ### Step 1: Express one of the variables in terms of the others From the third equation: $$a + b + c = 8 \implies a = 8 - b - c$$ ### Step 2: Substitute $$a = 8 - b - c$$ into the other equations Using this substitution in the first equation: $$2(8 - b - c) + b + 3c = 5$$ Expanding and simplifying: $$16 - 2b - 2c + b + 3c = 5$$ $$16 - b + c = 5$$ $$-b + c = -11 \implies b - c = 11 \tag{Equation 4}$$ Now, substitute $$a = 8 - b - c$$ into the second equation: $$5(8 - b - c) + 2b + 8c = 8$$ Expanding and simplifying: $$40 - 5b - 5c + 2b + 8c = 8$$ $$40 - 3b + 3c = 8$$ $$-3b + 3c = -32 \implies -b + c = -\frac{32}{3}$$

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Math Problem Analysis

Mathematical Concepts

Algebra
Systems of Linear Equations

Formulas

Substitution Method
Elimination Method

Theorems

Linear Combination of Equations

Suitable Grade Level

High School (Grades 10-12)