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# Solve this system of equations?

d=x+1200

d=2.5x

I'm having issues graphing d=x+1200. I need to know where the point of intersection is.

### 6 Answers

- GuillermoLv 79 years agoFavorite Answer
d = x +1200

The points of intersection are:

When x = 0, d = 1200, point (0, 1200) = d - int

When d = 0, x = - 1200, point (- 1200, 0) = x - int

Join these points with a line, done!

Solving the system:

2.5*x = x + 1200

1.5*x = 1200

x = 800

d = 2.5*x

d = 2.5*800

d = 2,000

(800, 2000), answer!

- 9 years ago
You do not need to graph them to find point of intersection

They are simultaneous equations

'x + 1200' and '2.5x' are both equal to 'd' and are therefore equal to each other so you can write '2.5x = x + 1200' and then begin to solve it

2.5x = x + 1200 (-x from both sides)

1.5x = 1200 (divide both sides by 1.5)

x = 800

now you know 'x = 800' you can work out 'd'

use one of the original equations

d = 2.5x

d = 2.5*800

d = 2000

point of intersection is d = 2000, x = 800

Source(s): A level maths - Ed HLv 49 years ago
Intersects at x=0, d=1200

Substitute 1st equation into 2nd

2.5x = x+1200

1.5x = 1200

x = 800

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- 9 years ago
To fnd the POI, you need to set both equations equal to each other so..

x+1200=2.5x

1200=1.5x

x=800

Plugging that back in to find y coordinate...

d=x+1200

d=800+1200

d=2000

Also..

d=2.5x

d= 2.5 * 800

d=2000

They're both the same so your POI is

(800, 2000)

Hope this helps

Source(s): Math knowledge - Anonymous9 years ago
2.5x=x+1200

1.5x=1200

x=800