What is algebraic expression and a point?

-An algebraic expression is a mathematical phrase that can contain ordinary numbers, variables (like x or y) and operators (like add,subtract,multiply, and divide).

- examples:
(i) 2x+y
(ii)3a+2y

-A point in geometry is a location. It has no size i.e. no width, no length and no depth. A point is shown by a dot. Points that are on the same line are called collinear points. A line is defined by two points and is written as shown below with an arrowhead.
example:
(1,2) is a point which is at a distance 1 unit from y axis and 2 units from x axis.