line axis intersectioni don't get what to do to find intersection of a line and x and y axis.

Expert Answers
hala718 eNotes educator| Certified Educator

Let the line be y = mx + b

The x-axis is given by the equation y= 0

To find the intersection between the line and the x-axis we find the points where y= y

==> mx + b = 0

Then, we solve for x.

Let the solution be x1. 

Then, the intersection point between the line and the x-axis is (x1, 0).

Now we know that the equation for the y-axis is x = 0.

==> Then, we will substitute with x= 0 into the equation of the line.

==> y= b

Then the intersection point between the line and the y-axis is ( 0, b).

pohnpei397 eNotes educator| Certified Educator

This depends on what you know about the line.  If you have the equation for the line, it's pretty easy to find the intercepts.

You know that the x intercept, for example, is the point on the line where y = 0.  So you take the equation and set y = 0 and solve for x.  Then you will have the coordinates of the x intercept.  Then you can do the same for the y intercept -- just set x = 0 and solve for y.

giorgiana1976 | Student

We know that when a line is intersecting x axis, the value of x is the solution of the equation.

We'll have the equation of the line y = ax + b (1).

Whne we want to find the solution of the equation of the line, we write:

ax + b = 0 (2)

x = -b/a

Comparing (1) and (2), we'll get y = 0.

So, the line is intercepting x axis in the point (-b/a , 0).

We'll conclude that if we want to find out the y intercepting point, we'll have to put x = 0.

y = ax + b

For x = 0 => y = a*0 + b

y = b

So, the line is intercepting y axis in the point (0 , b).