👤

Calculati X+Y,stiind ca xy+yx este patrat perfect .


Răspuns :

xy(barat)=10x+y
yx(barat)=10y+x  =.>
[xy(barat)+yx(barat)=10x+y+10y+x=11x+11y=k²
11(x+y)=k²=.>x+y=11  k²=121
xy+yx=11²
xy+yx=121
10x+y+10y+x=121
11x+11y=121
11*(x+y)=121
x+y=121:11
x+y=11