Answer:
Step-by-step explanation:
NOTE ================================
EQUATION OF A CIRCLE with center (a , b) and radius r :
(x - a)² + (y-b)² = r²
……………………………………………
x² − 14x + y² = 15
⇔ x² − 2×7x + 7² − 7² + y² = 15
⇔ x² − 2×7x + 49 − 49 + y² = 15
⇔ (x - 7)² − 49 + y² = 15
⇔ (x - 7)² + y² = 15 + 49
⇔ (x - 7)² + y² = 64
⇔ (x - 7)² + y² = 8²
Then radius of the circle is 8.
