Find all the 0's of this equation-3x^4+27x^2+1200=0

The zeroes of the equation 4i,-4i,5,-5Explanation: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 25Now 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