2x+5xy=14 { y-5xy=-9

Question

2x+5xy=14 { y-5xy=-9

Answer 1

}2x+5xy=14
}y-5xy=-9

2x+y=5 => y=5-2x

2x+5x(5-2x)=14
2x+25x-10x²-14=0
10x²-27x+14=0
D=27²-4*10*14=729-560=169=13²

x1=27+13/20=40/20=2 <=> y15-4=1
x2=27-13/20=14/20=7/10 <=> y2=5-14/10=3,6

ответ: (2; 1) (0,7; 3,6)