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## #1 2012-08-05 21:30:52

ac88218
Member
Registered: 2012-08-05
Posts: 3

### point-gradient form of a linear equation

hello,
Just wondering if anyone can help me out with this question my teacher set me, thanks
"Find the equation of a line with a gradient of -4 and an x-intercept of 5"
hope someone can help...

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## #2 2012-08-05 21:35:24

bob bundy
Registered: 2010-06-20
Posts: 8,321

### Re: point-gradient form of a linear equation

hi ac88218

just typing this up.  Stay on-line if you can.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #3 2012-08-05 21:36:26

bob bundy
Registered: 2010-06-20
Posts: 8,321

### Re: point-gradient form of a linear equation

The point gradient form looks like this:

You are told that m = -4 and that (5,0) is one point.  So

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #4 2012-08-05 21:39:48

ac88218
Member
Registered: 2012-08-05
Posts: 3

### Re: point-gradient form of a linear equation

Thanks,
I know the formula, I think I need to know how to find the y-intercept to keep going from here because I know how to do it with both intercepts,
if you could help me find out how that would be great

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## #5 2012-08-05 21:52:45

bob bundy
Registered: 2010-06-20
Posts: 8,321

### Re: point-gradient form of a linear equation

OK.

I did add some more to post 3 but I'll show you how to get the y intercept without knowing that equation.

As the gradient is minus 4, that will mean for every 1 you step left in the x direction, the y coordinate will go up by  4.

So step back a few points like this:

(5,0)  ... (4,4) ... (3,8) ... (2,12) ... (1,16) ... (0,20)

So the y intercept is (0,20)

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #6 2012-08-05 21:56:54

ac88218
Member
Registered: 2012-08-05
Posts: 3

### Re: point-gradient form of a linear equation

thanks so much, didn't realise it was that easy

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