Example What is the solution of the system of equations? \[ \begin{array}{l} -5 x+2 y=22 \\ 10 x+2 y=-8 \end{array} \] \[ \begin{array}{rlrl} 2(-5 x+2 y=22) \rightarrow-10 x+4 y & =44 & 10 x+2 y & =-8 \\ +10 x+2 y & =-8 & 10 x+2(6) & =-8 \\ 6 y & =36 & 10 x+12 & =-8 \\ y & =6 & 10 x & =-20 \\ x & =-2 \end{array} \] The solution is \( (-2,6) \). Show a different way to use elimination to solve the system of equations in the Example.
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One alternative approach using elimination is to align the equations by eliminating one variable directly. Start with the original equations: 1. \(-5x + 2y = 22\) 2. \(10x + 2y = -8\) To eliminate \(y\), subtract the first equation from the second. This will give you: \[ (10x + 2y) - (-5x + 2y) = -8 - 22 \] This simplifies to: \[ 15x = -30 \implies x = -2 \] Now substitute \(x = -2\) back into one of the original equations. Using the first one: \[ -5(-2) + 2y = 22 \implies 10 + 2y = 22 \implies 2y = 12 \implies y = 6 \] Thus, the solution remains \( (-2, 6) \). A fun tip with elimination is to keep an eye on coefficients; if they're out of sync, multiplying one or both equations to match them can create a clean path to simplification. Remember, avoidance of mistakes in sign handling and arithmetic is key—double-check your calculations!