If a graph shows the function y=3x what are the coordinates of the intercepts

graph{3x+5 [-10, 10, -5, 5]}

x

intercept:  

x

=

−

5

3

y

intercept:  

y

=

5

Explanation:

For a linear graph, the quickest way to sketch the function is to determine the  

x

and  

y

intercepts and draw a line between the two: this line is our graph.

Let's calculate the  

y

intercept first:

With any function,  

y

intercepts where  

x

=

0

.

Therefore, substituting  

x

=

0

into the equation, we get:

y

=

3

⋅

0

+

5

y

=

5

Therefore, the  

y

intercept cuts through the point (0,5)

Let's calculate the  

x

intercept next:

Recall that with any function:  

y

intercepts where  

x

=

0

.

The opposite is also true: with any function  

x

intercepts where  

y

=

0

.

If we substitute  

y

=

0

, we get:

0

=

3

x

+

5

Let's now rearrange and solve for  

x

to calculate the  

x

intercept.

−

5

=

3

x

−

5

3

=

x

Therefore, the  

x

intercept cuts through the point  

(

−

5

3

,

0

)

.

Now we have both the  

x

and  

y

intercepts, all we have to do is essentially plot both intercepts on a set of axis and draw a line between them

The graph of the function  

y

=

3

x

+

5

:

graph{3x+5 [-10, 10, -5, 5]}

the perimeter is increased by a factor of 2