Question

Resolva a equação biquadrada:
(x²-4)² +2 (x²+5)²=66

Answer 1

$(x^2-4)^2+2(x^2+5)^2=66 \\ x^4-8x^2+16+2(x^4+10x^2+25)=66 \\ x^4-8x^2+16+2x^4+20x+50=66 \\ 3x^4=-12x^2 \\ x^2=-4 \\ x= \sqrt{-4} \\ x=2i$

onde $i = \sqrt{-1}$