решите уравнение: 1-z^{2}=0; 3z^{2}-75=0

Question

решите уравнение: 1-z^{2}=0; 3z^{2}-75=0

Answer 1

9x^4+17х^2-2=0

x^2=t

9t^2+17t-2=0

D=17^2-(4*(-2)*9)=289+72=361

t1=(-17+19)/18=2/18=1/9

t2=-36/18=-2

 

X^2=1/9

x1=1/3

 

X^2=-2

Answer 2

1-z^2=0

D=0^2-4*(-1)*1=4

z1=2/(2*(-1))=-1
z2=-2/(2*(-1))=1

 

3z^2-75=0

D=0^2-4*3*(-75)=900

z1=30/(2*3)=30/6=5
z2=-30/(2*3)=-30/6=-5