Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

Pages: **1**

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

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...

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,613

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

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,613

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

Offline

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

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

Offline

**bob bundy****Moderator**- Registered: 2010-06-20
- Posts: 7,613

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

Offline

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

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

Offline

Pages: **1**