SOLUTION: I have no idea how to do circles and find the center and radius.
A circle has the equation of 7x^2 + 7y^2 + 42x +28y - 84 = 0.
Graph the circle using the center (h,k) and the r
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Question 779859: I have no idea how to do circles and find the center and radius.
A circle has the equation of 7x^2 + 7y^2 + 42x +28y - 84 = 0.
Graph the circle using the center (h,k) and the radius r. Find the intercepts, if any of the graph. Thank you in advance
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
Complete the squares:
Step 1. Add the additive inverse of the constant term to both sides.
Step 2: Multiply by the reciprocal of the coefficients on the 
and 
terms
Step 3: Rearrange with spaces so that you can create the sum of two quadratic trinomials, one in x and one in y
Step 4: Divide the first degree x term coefficient by 2, square the result and add to both sides of the equation. 6 divided by 2 is 3, 3 squared is 9, so:
Step 5: Repeat for the y terms:
Step 6: Sum the constants:
Step 7: Factor the two perfect square trinomials in the LHS:
^2\ +\ (y\ +\ 2)^2\ =\ 25)
Rewrite:
\right)^2\ +\ \left(y\ -\ (-2)\right)^2\ =\ 5^2)
Since the equation of a circle centered at )
with radius 
is:
^2\ +\ (y\ -\ k)^2\ =\ r^2)
You can determine 
by inspection.
John
Egw to Beta kai to Sigma
My calculator said it, I believe it, that settles it
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