posted by tiona on .
Given the equation x^2 +y^2+8y-65=0
(a) Write the equation in standard form.
(b) State the center, radius, and intercepts.
(c) Submit the graph
to write this in standard form, you use completing the square for both variables x and y.
x^2 + y^2 + 8y - 65 = 0
x^2 + (y^2 + 8y + 16) - 65 - 16 = 0
x^2 + (y + 4)^2 - 81 = 0
x^2 + (y + 4)^2 = 81
x^2 + (y + 4)^2 = 9^2
Center: C(0, -4)
Radius = 9
to get intercepts,
x-intercept: let y=0 and solve for x
y-intercept: let x=0 and solve for y
with center and radius known, you can graph this on a graphing paper. use a compass to draw the circle.
hope this helps~ :)