Question

以下三元二次方程该怎么解?a+c=-1 ,ac+b=-1 ,bc=-2 .求a,b,c

Answer 1

a+c=-1

a=-1-c

ac+b=-1

b=-1-ac=-1-(-1-c)c=-1+c+c^2

bc=-2

c(c^2+c-1)=-2

c^3+c^2-c+2=0

(c+2)(c^2-c+1)=0

c=-2

b=c^2+c-1=1

a=-1-c=-1+2=1

a=b=1,c=-2