What is the radius of a circle with the equation x^2 + y^2 – 14x + 10y = 250?
A) 9 units
B) 12 units
C) 15 units
D) 18 units

Question

What is the radius of a circle with the equation x^2 + y^2 – 14x + 10y = 250? 
  A)    9 units    
  B)    12 units    
  C)    15 units    
  D)    18 units

misty1212 · Answer

HI!!

misty1212 · Answer

do you know how to complete the square?   you have to do it twice here, once for x and once for y

flowey15 · Answer

no, I dont

misty1212 · Answer

then there is no way for you to solve this 
you have to make it look like $$(x-h)^2+(y-k)^2=r^2$$ to find $r$

flowey15 · Answer

I know that part..i just don't know how

misty1212 · Answer

i can show you if you like, it takes a few steps 
but if you have never seen completing the squarer, it might now make any sense

misty1212 · Answer

start with $$x^2-14x+y^2+10y=250$$ i.e group the terms together q

misty1212 · Answer

now for the x
what is half of 14?

flowey15 · Answer

7

misty1212 · Answer

and what is $7^2$?

flowey15 · Answer

49, think

misty1212 · Answer

yes 
so first step is to turn $$x^2-14x+y^2+10y=250$$ in to $$(x-7)^2+y^2+10y=250+49$$

misty1212 · Answer

now we do the same for y 
what is half of 10?

dinamix · Answer

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