1/gia su bo 3 so thuc \(x,y,z\) thoa \(x+1=y+z\) va \(xy+z^2-7z+10=0\) .Chung minh \(x^2+y^2=-z^2+12z-19\) 2/cho a,b,c la cac so thuc duong thoa man \(a^2+b^2+c^2=\left(a-b\right)^2+\left(b-c\right)^2+\left(c-a\right)^2\) a)tinh \(a+b+c\)biet \(ab+ac+bc=9\) b) Cmr neu \(c\ge a,c\ge b\) thi \(c\ge...
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1/gia su bo 3 so thuc \(x,y,z\) thoa \(x+1=y+z\) va \(xy+z^2-7z+10=0\) .Chung minh \(x^2+y^2=-z^2+12z-19\)
2/cho a,b,c la cac so thuc duong thoa man \(a^2+b^2+c^2=\left(a-b\right)^2+\left(b-c\right)^2+\left(c-a\right)^2\)
a)tinh \(a+b+c\)biet \(ab+ac+bc=9\)
b) Cmr neu \(c\ge a,c\ge b\) thi \(c\ge a+b\)
