Question

What are the solutions of the equation x6 + 6x3 + 5 = 0? Use factoring to solve.

Answer 1

Solution:

we have been asked to find the solution of the equation

$x^6 + 6x^3 + 5 = 0$

It can be solved using factoring as below:

$x^6 + 6x^3 + 5 = 0\\\\substitute, x^3=y\\\\y^2+6y+5=0\\\\y^2+5y+y+5=0\\\\y(y+5)+1(y+5)=0\\\\(y+5)(y+1)=0\\\\y=-1,-5\\\\\text{substitute back }y=x^3\\\\x^3=-1,-5\\\\x=-1,\sqrt[3]{-5} \\\\\text{These are the only real solutions}$

Answer 2

Its x^3 + 5)(x^3 + 1) = 0

x^3 + 5 = 0
x^3 = -5
x = cube root -5

x^3 + 1 = 0
x^3 = - 1
x = cube root -1
x = - 1