Question

Помогите решить уравнение 70

Answer 1

( $\sqrt{(x+7)(x-7}$ )^2 =-x^4+49x^2
(x+7)(x-7)=(-x^4+49x^2)^2
(x+7)(x-7)=x^8-98x^6+2401x^4
x^2-49=x^8-98x^6+2401x^4
x^8-98x^6+2401x^4=x^2-49
x^8-98x^6+2401x^4-x^2=-49
x^8-98x^6+2401x^4-x^2+49=0
x^8-98x^6+2401x^4-x^2+49/x-7=>
x^7+7x^6-49x^5-343x^4-x-7
x=7;-7