There are *positive* real numbers \(x\) and \(y\) which solve the equations \[2x + ky = 4, \qquad x+y = k\] for

all values of \(k\);

no values of \(k\);

\(k=2\) only;

only \(k>-2\).

There are *positive* real numbers \(x\) and \(y\) which solve the equations \[2x + ky = 4, \qquad x+y = k\] for

all values of \(k\);

no values of \(k\);

\(k=2\) only;

only \(k>-2\).