3x -4y + 2 =0 3x +5 =3 5x +2y =14 3x -2y =14

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1. $\left \{ {{3x -4y  =-2 } \atop {5x +2y =14  }} \right.$
   ⇔$\left \{ {{3x -4y  =-2 } \atop {10x+4y=28}} \right.$ 
   ⇔$\left \{ {{13x=26⇔x=2} \atop {10+2y=14}} \right.$ 
   ⇔$\left \{ {{x=2} \atop {2y=4}} \right.$ 
   ⇔$\left \{ {{x=2} \atop {y=2}} \right.$ 

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   $\left \{ {{3x +5y =3} \atop {  3x -2y =14}} \right.$ 
   ⇔$\left \{ {{7y=-11⇔y=\frac{-11}{7}} \atop {3x+\frac{22}{7}=14}} \right.$ 
   ⇔$\left \{ {{y=\frac{-11}{7}} \atop {3x=\frac{76}{7}}} \right.$ 
   ⇔$\left \{ {{y=\frac{-11}{7}} \atop {x=\frac{76}{21}}} \right.$

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