[" 69.The differential equation of the "],[" family of straight lines which are at a "],[" distance '3' units from origin is- "]

Find the differential equation of the family of all straight lines.

The differential equation of the family of straight lines parallel to x-axis is ____.

Write the differential equation of the family of straight lines parallel to the y-axis.

The differential equation of all straight lines which are at a fixed distance of 10 units from the origin is (y-xy_(1))^(2) = A(1+y_(1)^(2)) then A is equal to ________.

The differential equation of all straight lines which are at a fixed distance of 10 units from the origin is (y-xy_(1))^(2) = A(1+y_(1)^(2)) then A is equal to ________.