Math Problem Statement

solve it in normal way not augmented matrix

Solve the following system of equations: \[ \begin{cases} x_2 + 4x_3 = -5 \\ x_1 + 3x_2 + 5x_3 = -2 \\ 3x_1 + 7x_2 + 7x_3 = 6 \end{cases} \] Solve it in the normal way, not using an augmented matrix.

Solution

To solve the system of equations without using an augmented matrix, let's rewrite and solve it step-by-step. The given system is:

x_2 + 4x_3 = -5 \\ x_1 + 3x_2 + 5x_3 = -2 \\ 3x_1 + 7x_2 + 7x_3 = 6 \end{cases}$$ ### Step 1: Solve for $$x_2$$ in terms of $$x_3$$ from the first equation From the first equation: $$x_2 + 4x_3 = -5$$ $$x_2 = -5 - 4x_3$$ ### Step 2: Substitute $$x_2 = -5 - 4x_3$$ into the second and third equations Substitute into the second equation: $$x_1 + 3(-5 - 4x_3) + 5x_3 = -2$$ Simplify: $$x_1 - 15 - 12x_3 + 5x_3 = -2$$ $$x_1 - 15 - 7x_3 = -2$$ $$x_1 = 13 + 7x_3$$ Now, substitute $$x_2 = -5 - 4x_3$$ into the third equation: $$3x_1 + 7(-5 - 4x_3) + 7x_3 = 6$$ Simplify: $$3x_1 - 35 - 28x_3 + 7x_3 = 6$$ $$3x_1 - 35 - 21x_3 = 6$$ $$3x_1 = 41 + 21x_3$$ Substitute \( x_1 = 13 + 7x_3

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Math Problem Analysis

Mathematical Concepts

Linear Algebra
System of Equations
Substitution Method

Formulas

Substitution method for solving linear systems

Theorems

Basic rules of algebra for solving systems of equations

Suitable Grade Level

College-level Linear Algebra or High School Advanced Algebra