Question 258453
You can factor the equation.
{{{x^4+7x^2-144=(x^2+16)(x^2-9)}}}
Real zeros:
{{{x^2-9=0}}}
{{{x^2=9}}}
{{{x=0 +- 3}}}
x=3 and x=-3 with multiplicity of 1.
.
.
.
Complex zeros:
{{{x^2+16=0}}}
{{{x^2=-16}}}
{{{x=0 +- 4i}}}
x=4i and x=-4i with multiplicity of 1.
.
.
.
{{{ graph( 300, 300, -5, 5, -50, 50,x^4+7x^2-144) }}}