For the ellipse
\[
\frac{x^2}{36}+\frac{y^2}{25}=1,
\]
the straight line
\[
2x+y-5=0
\]
is
Show Hint
For the ellipse
\[
\frac{x^2}{a^2}+\frac{y^2}{b^2}=1,
\]
the line
\[
y=mx+c
\]
is tangent if
\[
\boxed{c^2=a^2m^2+b^2.}
\]
If this condition is not satisfied but the line intersects the ellipse at two points, it is a chord.