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Grade Upto college levelAlgebra

the number of real solutions of the system

x+y+z=1,2xy-z2=1 is

I am getting 1 as the ans but answer given is 3

Profile image of sudarshan gupta
16 Years agoGrade Upto college level
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1 Answer

Profile image of PARTH ARORA
15 Years ago

by simple analysis we see that 

x=1 y=1 z=-1 satisfy both the equations 

z= 1- ( x+y)

put in second equation 

 

2xy - { 1-( x+y)}^2  =1 

2xy -1 - (x+y)^2 + 2(x+y)=1

2(X+Y)-(X^2 +Y^2)=2 

only has one solution