Question

determinati numerele naturale xy stiind ca sunt indeplinite simultan conditiile : x-y=120 x=y:4

Answer 1

x-y=120
x=y+120
x=y:4
y+120=y:4
4(y+120)=y
4y+480=y
-3y=480
y=-160
x=-160+120
x=-40
{x,y}={-40,-160}