Question 299952
Find the x and y intercepts. 
To find the x-intercept, set y=0 and solve for x.
{{{ x^2/25+y^2/16=1 }}}
{{{ x^2/25=1 }}}
{{{ x^2=25}}}
{{{ x=0 +- 5}}}
(-5,0) and (5,0)
To find the y-intercept, set x=0 and solve for y.
{{{ x^2/25+y^2/16=1 }}}
{{{ y^2/16=1 }}}
{{{ y^2=16 }}}
{{{y= 0 +- 4}}}
(0,-4) and (0,4)
Plot the points. 


{{{drawing(300,300,-6,6,-6,6,grid(1),
circle(-5,0,.25),
circle(5,0,.25),
circle(0,-4,.25),
circle(0,4,.25))}}}
.
.
.
Then sketch an ellipse fitting those points. 
{{{drawing(300,300,-6,6,-6,6,grid(1),
circle(-5,0,.25),
circle(5,0,.25),
circle(0,-4,.25),
circle(0,4,.25),graph(300,300,-6,6,-6,6,
sqrt(16*(1-x^2/25)),
-sqrt(16*(1-x^2/25)))
)}}}