# How to draw the function x+5<7

1. Aug 12, 2013

### Manula

I am just interested in knowing, how to draw the function x+5<7 in a cartesian plane.
Since the definition of a function is, If For a certain input, there exist an out, then it is a function.
Is x+5<7 is a valid function then?

2. Aug 12, 2013

### micromass

Staff Emeritus
What you wrote is an inequality, not a function.

3. Aug 12, 2013

### junaid314159

If the inequality has only one variable (as yours does), you would graph the solution on a number line. If the inequality has two variables (x and y), then you could graph the solution on a Cartesian plane.

4. Aug 15, 2013

### HallsofIvy

Staff Emeritus
To draw a graph of this inequality, first draw the graph of the corresponding equation. x+ 5= 7. That. of course, is the same as "x= 2". It's graph, in a two dimensional "xy" graph, is the vertical line at x= 2. The set of points for which x+ 5< 7 is the set of points for which x< 2. That is, all points to the left of that vertical line.

5. Aug 16, 2013

### Manula

But if we take y=(x+5) and then, draw the graph, wouldn't it give different results??

6. Aug 17, 2013

### arildno

True.
Of the simple reason that the first inequality does not place any sort of restrictions on the y-coordinate in the points' (x,y) coordinate pairs.