Respuesta :

The zeroes of the equation 4i,-4i,5,-5

Explanation:

Given:

[tex]-3x^4+27x^2+1200=0[/tex]

To Find:

The  0's of the equation=?

Solution:

We can  write the equation by taking minus sign common from left hand side and the equation will become  

[tex]3x^4-27 x^2-1200=0[/tex]

Now, Let[tex]x^2=t[/tex]

And put the value of [tex]x^2[/tex] in the above equation and then we will get

[tex]3t^2-27t-1200=0[/tex]

Now take 3 common from left hand side of the equation  So equation would become

[tex]t^2-9t-400=0[/tex]

[tex](x+16)(x-25)=0[/tex]

hence the roots are t= -16 and 25

Now that we know the value(s) of  t , we can calculate  x  since  x  is  [tex]\sqrt{t}[/tex]

Since we are speaking 2nd root, each of the two imaginary solutions of has 2 roots

[tex]\sqrt{t}= x[/tex]

[tex] x=\pm\sqrt{-16}[/tex]

x= [tex]\pm4i[/tex]

[tex] x=\pm\sqrt{25}[/tex]

x= [tex]\pm5[/tex]

Hence the roots are 4i,-4i,5,-5