Question

Trebuie sa rezolv exercitiile astea la matematica

Answer 1

  $G1. \left \{ {{x+2y=4} \atop {x-y=0}} \right. \\ \\ \left \{ {{x+2y=4} \atop {x=y}} \right. \\ \\ \left\{ {{y+2y=4} \atop {x=y}} \right. \\ \\ \left \{ {{y= \frac{4}{3}} \atop {x= \frac{4}{3} }} \right.$

$G2. \left \{ {{x-5y=1} \atop {3x+2y=3}} \right. \\ \\ \left \{ {{x=1+5y} \atop {3(1+5y)+2y=3}} \right. \\ \\ \left\{ {{y=0} \atop {x=1+5\cdot0=1}} \right. \\ \\ \left \{ {{y= 0}} \atop {x=1}} \right.$


$G3. \left \{ {{4x-2y=1} \atop {x+y=0}} \right. \\ \\ \left \{ {{4x-2y=1} \atop {x=-y}} \right. \\ \\ \left\{ {{-4y-2y=1} \atop {x=-y}} \right. \\ \\ \left \{ {y=- \frac{1}{6}} \atop {x=-y= \frac{1}{6} }} \right.$


$G4. \left \{ {{3x-y=2} \atop {2x+y=5}} \right. \\ \\ \left \{ {{3x-2=y} \atop {y=5-2x}} \right. \\ \\ \left\{ {{3x-2+2x=5} \atop {y=5-2x}} \right. \\ \\ \left \{ {5x=7} \atop {y=5-2x}} \right. \\ \\ \left \{ {{x= \frac{7}{5}} \atop {y=5-2x=5-2\cdot \frac{7}{5}= \frac{11}{5}}} \right.$