Question

помогите плизз x^2-6x+2(x-3)^2=81

 

$x^2-6x+2(x-3)^2=81$

Answer 1

$x^2-6x+2(x-3)^2=81\ x^2-6x+2(x^2-6x+9)-81=0\ x^2-6x+2(x^2-6x)-63=0\ x^2-6x=a\ a+2a=63\ 3a=63\ a=21\ x^2-6x-21=0\ D=36-4*(-21)=36+84=120\ x_1=frac{6-2sqrt{30}}{2}=3-sqrt{30}\ x_1=frac{6+2sqrt{30}}{2}=3+sqrt{30}$