Algebra quesiton?

Question

B______M________C

(8, -1) (-4, 9) (x, y)

Find the coordinates of C and find BC.

so, i got BM to equal 2 sq.rout 6

Answer 1

uh ?

Answer 2

You're doing this the way hard way. :)

I'm assuming that M is the midpoint of BC.  If so:

Midpoint(x, y) = ((x1+x2)/2),((y1+y1)/2)

This gives you two separate equations when you split up the x's from the y's.

x of midpoint = (x1 + x2)/2 and

y of midpoint = (y1 + y2)/2

If B is point "1" then x1 = 8 and y1 = -1

If C is point "2" then it's x2 and y2 that you don't know

If M is the midpoint, then x of midpoint = -4 and y of midpoint = 9

x of midpoint = (x1 + x2)/2

9 = (8 + x2)/2   <--- multiply both sides by 2

18=8 + x2 <--- isolate for x

18-8=x2

10 = x2

So now you know C is the point (10, y2) and you can use the second equation in the exact same way to figure out what y2 is.

Is that enough to help?