\\ 5\sqrt{x^4-20x^2+4}=7x^2+20x-14\\25(x^4-20x^2+4)=49x^4+400x^2+196+280x^3-196^2-520x\\25(x^4-20x^2+4)-49x^4-400x^2-196-280x^3+196^2+520x=0\\25x^4-500x^2+100-49x^4-400x^2-196-280x^3+196^2+520x=0\\-24x^4-704x^2-96-280x^3+560=0\\-8(3x^4-6x^2+100x^2-6x^2+12+16x^3+20x^3-40x-30x)=0\\3x^4-6x^2+100x^2-6x^2+12+16x^3+20x^3-40x-30x=0\\3x^2(x^2+5x-2)+20x(x^2+5x-2)[\tex]
х∈[-∞;-2-√6]∪[-2-√6;-2+√6]∪[2+√6;+∞]
Теперь находим корни уровнения.
\\ 5\sqrt{x^4-20x^2+4}=7x^2+20x-14\\25(x^4-20x^2+4)=49x^4+400x^2+196+280x^3-196^2-520x\\25(x^4-20x^2+4)-49x^4-400x^2-196-280x^3+196^2+520x=0\\25x^4-500x^2+100-49x^4-400x^2-196-280x^3+196^2+520x=0\\-24x^4-704x^2-96-280x^3+560=0\\-8(3x^4-6x^2+100x^2-6x^2+12+16x^3+20x^3-40x-30x)=0\\3x^4-6x^2+100x^2-6x^2+12+16x^3+20x^3-40x-30x=0\\3x^2(x^2+5x-2)+20x(x^2+5x-2)[\tex]
х∈[-∞;-2-√6]∪[-2-√6;-2+√6]∪[2+√6;+∞]
Теперь находим корни уровнения.