Question 1025983
{{{x^4=7(x^2)+18}}}
Solve for x.
Arrange as a quadratic equation
{{{x^4 - 7x^2 - 18 = 0 }}}
Factor
{{{(x^2-9)(x^2+2) = 0}}}
The positive solution is what we want here
{{{x^2 = 9}}}
Two solutions
{{{x = sqrt(9)}}} 
x = 3
and
{{{x = -sqrt(9)}}}
x = -3
:
looks like this
{{{ graph( 300, 200, -6, 6, -50, 50, x^4-7x^2-18) }}}