Answer:
radius = 11
Step-by-step explanation:
The equation of a circle in general form is
x² + y² + 2gx + 2fy + c = 0
with radius =
x² + y² - 20x + 14y + 28 = 0 ← is in general form
with 2g = - 20 ⇒ g = - 10
2f = 14 ⇒ f = 7 and c = 28, thus
radius = =
=
= 11
Answer:
d = -1/3, 0
Step-by-step explanation:
Subtract the constant on the left, take the square root, and solve from there.
(6d +1)^2 + 12 = 13 . . . . given
(6d +1)^2 = 1 . . . . . . . . . .subtract 12
6d +1 = ±√1 . . . . . . . . . . take the square root
6d = -1 ±1 . . . . . . . . . . . .subtract 1
d = (-1 ±1)/6 . . . . . . . . . . divide by 6
d = -1/3, 0
_____
Using a graphing calculator, it is often convenient to write the function so the solutions are at x-intercepts. Here, we can do that by subtracting 13 from both sides:
f(x) = (6x+1)^ +12 -13
We want to solve this for f(x)=0. The solutions are -1/3 and 0, as above.
