Substituting the point p (2 2,3) into the equation, we get: 3=2k, that is, k=3/2.
∴ The equation of line L is 3x-2y = 0；;
② When the intercept of a straight line on two coordinate axes is not 0, let the equation of straight line L be: x/a+y/a= 1.
Substituting the point p (2 2,3) into the equation gives 2/a+3/a= 1, that is, a=5.
The equation of the straight line l is: x+y-5 = 0.