Question

решите систему уравнений x-y=7 lg(2x+y+2)=1

Answer 1

Объяснение:

$\left \{ {x-y=7} \atop {lg(2x+y+2)=1}} \right. \ \ \ \ \left \{ {{y=x-7} \atop {lg(2x+x-7+2)=1}} \right. \ \ \ \ \left \{ {{y=x-7} \atop {lg(3x-5)=1}} \right.\ \ \ \ \left \{ {{y=x-7} \atop {3x-5=10^1}} \right. \\\left \{ {{y=x-7} \atop {3x=10\ |:3}} \right. \ \ \ \ \left \{ {{y=-2} \atop {x=5}} \right. .$

Ответ: (5;-2).