Question

Решить систему.
$left { {{2(x+y)=40} atop {xy=51}} right.$

Answer 1

2(x+y)=40
xy=51
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x+y=20
xy=51
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x=20-y
(20-y).y=51,20y-y²=51,y²-20y+51=0,D=400-204=196,√D=√196=14
y1=(20+14)/2=34/2=17, y2=(20-14)/2=6/2=3
x1=20-17=3, x2=20-3=17
/x,y/=/3,17/ ili /x,y/=/17,3/