How do you solve the system 10y=x^210y=x2 and x^2-6=-2yx26=2y?

1 Answer
Jul 15, 2016

We have two solutions (-sqrt5,1/2)(5,12) and (sqrt5,1/2)(5,12)

Explanation:

As 10y=x^210y=x2 and x^2-6=-2yx26=2y, putting value of x^2x2 from first equation into second we get

10y-6=-2y10y6=2y or

10y+2y+6-6=-2y+2y+610y+2y+66=2y+2y+6 or

12y=612y=6 or

y=6/12=1/2y=612=12.

Hence, x^2=10×1/2=5x2=10×12=5 or

x^2-5=0x25=0 or

x^2-(sqrt5)^2=0x2(5)2=0 or

(x-sqrt5)(x+sqrt5)=0(x5)(x+5)=0

Hence, either x-sqrt5=0x5=0 i.e. x=sqrt5x=5

or x+sqrt5=0x+5=0 i.e. x=-sqrt5x=5

Hence we have two solutions (-sqrt5,1/2)(5,12) and (sqrt5,1/2)(5,12)