Example

Solving {4x3z=53y+2z=73x+4y=6\left\{\begin{array}{l} 4x - 3z = -5 \\ 3y + 2z = 7 \\ 3x + 4y = 6 \end{array}\right. by Elimination

To solve the linear system {4x3z=53y+2z=73x+4y=6\left\{\begin{array}{l} 4x - 3z = -5 \\ 3y + 2z = 7 \\ 3x + 4y = 6 \end{array}\right. using the elimination method, systematically pair equations to eliminate variables. First, eliminate zz from the first two equations by multiplying the first equation by 22 (yielding 8x6z=108x - 6z = -10) and the second equation by 33 (yielding 9y+6z=219y + 6z = 21). Adding these equations cancels zz to produce a new equation: 8x+9y=118x + 9y = 11. Pairing this new equation with the unused third equation creates a two-variable system: {8x+9y=113x+4y=6\left\{\begin{array}{l} 8x + 9y = 11 \\ 3x + 4y = 6 \end{array}\right.. Next, eliminate yy by multiplying the first equation by 44 to obtain 32x+36y=4432x + 36y = 44 and the second equation by 9-9 to create 27x36y=54-27x - 36y = -54. Adding these equations isolates xx, giving 5x=105x = -10, which simplifies to x=2x = -2. Substituting x=2x = -2 back into the third original equation (3x+4y=63x + 4y = 6) yields 3(2)+4y=63(-2) + 4y = 6, which allows deduction of y=3y = 3. Placing y=3y = 3 into the second original equation (3y+2z=73y + 2z = 7) yields 3(3)+2z=73(3) + 2z = 7, revealing z=1z = -1. The final solution is the ordered triple (2,3,1)(-2, 3, -1).

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Updated 2026-06-29

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