Math Is Fun Forum

tristan1

Member

Registered: 2005-11-19

Posts: 6

Straight Line Graph Equations

I have a task where I have to find the equation of ....

A line that passes through (0,7) at a gradient of 3.

* I Think this one is 3x+7*

A line that passes through (2,3) at a gradient of 2.

A line that passes through (4,3) at a gradient of -1.

A line that passes through (2,1) at a gradient of 4,5.

A line that passes through (4,5) and (6,7)

A line that passes through (0,5) at a gradient of (3,2).

ryos

Member

Registered: 2005-08-04

Posts: 394

Re: Straight Line Graph Equations

Your first equation is correct. It's in the form y=mx + b, where m is the slope and b is the y-intercept. b was easy to find because it was given to you, but not all problems are so nice. In this case, point-slope form (y = y1 + m(x - x1)) is your friend. So:

y= 3 + 2(x - 2)
y= 3 - (x - 4)
y= 1 + 4.5(x - 2)

etc.

---

El que pega primero pega dos veces.

tristan1

Member

Registered: 2005-11-19

Posts: 6

Re: Straight Line Graph Equations

y= 3 + 2(x - 2)
y= 3 - (x - 4)
y= 1 + 4.5(x - 2)

etc.

Are these the final answers? I'm unsure.

tristan1

Member

Registered: 2005-11-19

Posts: 6

Re: Straight Line Graph Equations

Please confirm for me these are the final answers and they dont need simplifying...

A line that passes through (0,7) at a gradient of 3 = 3x+7
A line that passes through (2,3) at a gradient of 2 = y= 3 + 2(x - 2)
A line that passes through (4,3) at a gradient of -1 = y= 3 - (x - 4)

tristan1

Member

Registered: 2005-11-19

Posts: 6

Re: Straight Line Graph Equations

Sorry for posting again, but I just realized these are the actual questions:

A line that passes through (0,7) at a gradient of 3.
^I Think this one is 3x+7^

A line that passes through (2,3) at a gradient of 2.
A line that passes through (4,3) at a gradient of -1.

A line that passes through (2,1) and (4,5)
A line that passes through (5,4) and (6,7)
A line that passes through (0,5) and (3,2).

Last edited by tristan1 (2005-11-19 05:53:06)