# What are the co-ordinates (x and y values) at the intercepts; ie. when x=0 and when y=0 in terms of the following equation: x+3y-7=0 Where intercept line x+3y-7 ox and oy?

durbanville | High School Teacher | (Level 2) Educator Emeritus

Posted on

I do hope that your question has been edited in terms of your intention. To "solve ' this, it needs to be an equation; for example

`x+3y-7=0` rather than just `x+3y-7` which is simply an expression. When we calculate co-ordinates, we use the equation. In this case, it is a straight line or linear equation. We find x when y=0 and we also find y when x=0.

`therefore`  when x=0:   ` 0+3y-7=0` (If your equation does not equal 0 substitute the value accordingly.)

`therefore 3y-7=0`

`therefore 3y=7`

`therefore y=7/3`

So the co-ordinates of the y-intercept (where x=0) are `(0;7/3)`

Always place the x value first.

Now do the same thing when y=0 `therefore x+3y-7=0` becomes

`x+3(0)-7=0`

`therefore x-7=0`

`therefore x=7`

So  the co-ordinates of the x-intercept (where y=0) are `(7;0)`

Note x always comes first.

If you were drawing the graph to form a line you can plot as follows. The line would continue but note the points (the dots) on the y-axis and the x-axis.

Ans: y intercept (0;7/3) x-intercept (7;0)