Question

what is the radius of the circle 4x²+4y²-20x+12y-15=0​

Answer 1

Answer:

3.5 = 7/2

Step-by-step explanation:

The given equation is:

4 x² + 4 y² — 20 x + 12 y — 15 = 0 ———-(1)

Dividing by 4 we get

x² + y² — 5 x + 3 y —15/4 = 0

=> [(x)² — 2. (5/2). x + (5/2)²] + [(y)² + 2.(3/2) y + (3/2)²] = 15/4 + (5/2)² + (3/2)²

=> [x — 5/2]² + [y + 3/2]² = 15/4 + 25/4 + 9/4 = 49/4 =(7/2)²

The equation of the circle

(x — 5/2)² + (y + 3/2)² = [7/2]² = r²

The radius of the circle r = 7/2