# Linear Applications

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• Dec 29th 2009, 06:03 PM
Tawar
Linear Applications
hello..
um i need some help to understand these questions please..

1. The length of the line joining A(2,-1) and B(5,y) is 5 unit. find y.

Please the only thing um stuck on is i dont get what 5 units means???

2.The point (h,k)lies on the line y=x+1 and is 5 units from the point (0,2). write down two equations connecting h and k..Again i dont understand the 5 unit..

PLease someone be niice enough and help me out..Much aprreciated it..Thankyou

Peace Out
• Dec 29th 2009, 06:16 PM
mr fantastic
Quote:

Originally Posted by Tawar
hello..
um i need some help to understand these questions please..

1. The length of the line joining A(2,-1) and B(5,y) is 5 unit. find y.

Please the only thing um stuck on is i dont get what 5 units means???

2.The point (h,k)lies on the line y=x+1 and is 5 units from the point (0,2). write down two equations connecting h and k..Again i dont understand the 5 unit..

PLease someone be niice enough and help me out..Much aprreciated it..Thankyou

Peace Out

1. From the distance formula: Solve $5^2 = (2 - 5)^2 + (-1 - y)^2$ for y.

2. The first equation is obviously h = k + 1.

The second equation is found by noting that the distance between the point (h, k) and (0, 2) is 5 units. Now apply the distance formula.
• Dec 30th 2009, 08:59 AM
HallsofIvy
Quote:

Originally Posted by Tawar
hello..
um i need some help to understand these questions please..

1. The length of the line joining A(2,-1) and B(5,y) is 5 unit. find y.

Please the only thing um stuck on is i dont get what 5 units means???

5 inches or 5 feet or whatever units you are measuring distance in. The distance from A to B is $\sqrt{(2- 5)^2+ (-1-y)^2}= 5$ so $9+ (y+1)^2= 25$ solve that for y.

Quote:

2.The point (h,k)lies on the line y=x+1 and is 5 units from the point (0,2). write down two equations connecting h and k..Again i dont understand the 5 unit..
Since (h, k) is on y= x+1, k= h+1. Since it is 5 "units" (again, just whatever you are measuring distance in) from (0,2), $\sqrt{(h-0)^2+ (k- 2)^2}= 5$ or just $h^2+ (k-2)^2= 25$.

Quote:

PLease someone be niice enough and help me out..Much aprreciated it..Thankyou

Peace Out