Question 981342
If eccentricity is the number e, then e is ratio of focal distance to main axis length.



Your eccentricity indicates  {{{0.5=(1.2-(-1.2))/(2a)}}}
{{{0.5=2.4/(2a)}}}
{{{0.5=1.2/a}}}
{{{a=1.2/0.5}}}
{{{a=2.4}}}


focal distance from center, a and b in an ellipse are related through  {{{c^2=a^2-b^2}}}, using c for distance from center to either focus.
{{{-b^2=c^2-a^2}}}
{{{b^2=a^2-c^2}}}
-
{{{b^2=2.4^2-1.2^2}}}
{{{b^2=4.32}}}


Fill the information into standard form ellipse equation.
{{{highlight(x^2/5.76+y^2/4.32=1)}}}