Given a point x(a,b) a line ,L1 is passing through x and parallel to x-axis what is the equation of L1 another line L2 passing through x and parallel y-axis what is the equation of L2

When a straight line is parallel to x-axis all points on the line have the same ordinate b.

Equation on this line is y = b

When a straight line is parallel to y-axis all points on the line have the same abscissa a.

Equation on this line is x = a

In this case:

Equation of L1:

y = b

Equation of L2:

x = a