you are asked to nd all real and complex solutions of the gi
you are asked to nd all (real and complex) solutions of the given equation.
x^6 + 7x^3 - 8 = 0
Solution
x^6 + 7x^3 - 8 = 0
Let x^3 =y
y^2 +7y -8 =0
y^2 +8y -y -8 =0
y(y +8) -1(y+8) =0
(y -1)(y +8) =0
y =1
x^3 =1 ----> x^3 -1 =0
(x-1)(x^2 +x +1) =0
x = 1 ; x = (1 +/- sqrt(1-4) )/2 = 0.5 +/- isqrt3
y +8 =0 ---> x^3 +8 =0
x = -2 , 1 +isqrt3 , 1 - isqrt3
Solution : x = -2 , 1 , 0.5 - isqrt3 , 0.5 + isqrt3, 1 +isqrt3 , 1 - isqrt3
