Few Linear Equation Questions.

• Jun 22nd 2013, 10:11 PM
Asthuran00
Few Linear Equation Questions.
I just recently finished up a unit that has to do with Linear Equations and there are a couple left over questions that I'm not 100% confident on. Thanks in advance for the help, and I'll post the question / my answers below.

QUESTION:

24)

The endpoints of a line segment are A(-7, -1) and B(5, 5).

a) Show that the origin, (0, 0), lies on the right bisector of AB.

b) Determine the equation of the circle with center (0, 0) and passing through both A and B.

24)

a)

y = -2x
0 = -2(0)
0 = 0

b)

Point A(-7, -1)
x^2 + y^2 = r^2
-7^2 + -1^2 = r^2
49 + 1 = r^2
50 = r^2
r = 7.07

Point B(5, 5)
x^2 + y^2 = r^2
5^2 + 5^2 = r^2
25 + 25 = r^2
50 = r^2
r = 7.07

It's not so much that I don't understand the math I'm doing, I'm just not sure if I'm giving them what they're asking for exactly - especially on 24 b, I'm not sure if they want two separate equations, one for each point, or if there's one equation I'm supposed to give.

Thanks so much!
• Jun 23rd 2013, 02:45 AM
chiro
Re: Few Linear Equation Questions.
Hey Asthuran00.

I wouldn't worry too much about the interpretation: you answered what they asked for and that's what is important here.

Also for question a) you should probably write the line in terms of t where t = 1 corresponds to (5,5) and t = -1 corresponds to (-7,-1) and then show that t = 0 corresponds to (0,0).

Keep in mind that your answer is right, but when you asked for the bisector it's a good idea if you have some evidence that the point does divide the line into two equal parts.
• Jun 23rd 2013, 02:51 AM
Asthuran00
Re: Few Linear Equation Questions.