A)
9 units
B)
12 units
C)
15 units
D)
18 units
4 Answers

assuming you mean x^2 + y^2 − 14x + 10y = 250
∴ x^2 − 14x + y^2 + 10y = 250
∴ x^2 − 14x + (14/2)^2 + y^2 + 10y + (10/2)^2 = 250 + (14/2)^2 + (10/2)^2
∴ (x − 7)^2 + (y + 5)^2 = 324
∴ (x − 7)^2 + (y + 5)^2 = 18^2
the radius is 18 units

You need to complete the square in order to do this..
x^2 + y^2 14x + 10y = 250
Completing the square gives you
(x7)^2 + (y+5)^2 = 324
Since the equation of a circle gives you r^2 you just take the square root
sqrt(324) = 18
So the answer is D

r^2=2504925=..

d