Question 21481
Solve for x:
{{{2x^4 - 26x^2 + 72 = 0}}} Factor out a 2.
{{{2(x^4 - 13x^2 + 36) = 0}}} Factor the parentheses.
{{{2(x^2 - 4)(x^2 - 9) = 0}}} Factor the parentheses again.
{{{2(x + 2)(x - 2)(x + 3)(x - 3) = 0}}} Apply the zero product principle.
{{{(x + 2) = 0}}} and/or {{{(x - 2) = 0}}} and/or {{{(x + 3) = 0}}} and/or {{{(x - 3) = 0}}}

The roots are:

x = -2
x = 2
x = -3
x = 3