$x^4-x^3y+x^2y^2=1$ và $ x^3y-x^2+xy=-1$
Giải hệ phương trình $x^4-x^3y+x^2y^2=1$ và $ x^3y-x^2+xy=-1$
Started By hanh7a2002123, 17-12-2016 - 07:20
#1
Posted 17-12-2016 - 07:20
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#2
Posted 17-12-2016 - 08:48
$(1)\Leftrightarrow x^{4}-2x^{3}y+x^{2}y^{2}+x^{3}y=1\Rightarrow x^{3}y=1-(x^{2}-xy)^{2}(*)$
$(2)\Leftrightarrow x^{3}y=-1+x^{2}-xy(**)$
Đặt $t=x^{2}-xy$
Từ $(*),(**)\Rightarrow 1-t^{2}=-1+t\Rightarrow t=....$ thay vào tìm x,y
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