Question

4x+3y=17
2x+5y=19
2 способом сложенте и подстановка​

Answer 1

Объяснение:

Сложение:

$\left \{ {{4x+3y+2x+5y=19+17} \atop {2x+5y=19}} \right.$

$\left \{ {{6x+8y=36} \atop {2x+5y=19}} \right.$

$\left \{ {{6x+8y=36} \atop {2x=19-5y}} \right.$

$\left \{ {{6x+8y=36} \atop {x=9,5-2,5y}} \right.$

$\left \{ {{6(9,5-2,5y)+8y=36} \atop {x=9,5-2,5y}} \right.$

$\left \{ {{57-15y+8y=36} \atop {x=9,5-2,5y}} \right.$

$\left \{ {{-7y=21} \atop {x=9,5-2,5y}} \right.$

$\left \{ {{y=3} \atop {x=9,5-2,5*3}} \right.$ $\left \{ {{y=3} \atop {x=2}} \right.$

Подстановка

$\left \{ {{4*\frac{19-5y}{2} +3y=17} \atop {x=\frac{19-5y}{2} }} \right.$$\left \{ {{\frac{76-20y+6y-34}{2} =0} \atop {x=\frac{19-5y}{2} }} \right.$$\left \{ {{\frac{-14y+42}{2}=0 } \atop {x=\frac{19-5y}{2} }} \right.$$\left \{ -14y=-42 } \atop {x=\frac{19-5y}{2} }} \right.$ $\left \{ y=3} \atop {x=\frac{19-5*3}{2} }} \right.$$\left \{ y=3} \atop {x=\frac{4}{2} }} \right.$$\left \{ y=3} \atop {x=2} \right.$