+0  
 
0
207
1
avatar

Suppose you graphed every single point of the form $(2t + 3, 3-3t)$. For example, when $t=2$, we have $2t + 3 = 7$ and $3-3t = -3$, so $(7,-3)$ is on the graph. Explain why the graph is a line, and find an equation whose graph is this line.

Guest Nov 23, 2017
 #1
avatar+87294 
+2

 

This graphs a line because for every increase in t by 1, x changes by 2 and y changes by -3

 

We only need two points to find a line

 

If t  = 0   we have the point  (3,3)

If t  = 1, we have the point  (5,0)

 

The slope of this line is       -3/2    [ just as we suspected  !!!! ] 

And using (5,0), the equation of the line is

 

y  = (-3/2)(x - 5)

 

y =  (-3/2)x + 15/2

 

To see that this is true.....when  t  = 2,   x = 7    and y  = -3

 

So    

 

y = (-3/2)(7) + 15/2

 

y = -21/2 + 15/2

 

y = -6/2   =    -3    

 

 

cool cool cool

CPhill  Nov 23, 2017
edited by CPhill  Nov 23, 2017

14 Online Users

New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.