The circle equation is in the format (x – h)² + (y – k)² = r², with the center being at the point (h, k) and the radius being "r".
QUESTION 11. Equation x²+y²+10x-14y-7 =0 can be rewritten as: x²+10x+25 + y² -14y + 49 -7 - 25 - 49=0 It can be factories as (x + 5)² + (y – 7)² = 9²
Therefore the radius equals 9 and the center is (-5,7)
QUESTION 12. From equation (x + 4)² + y² = 121
The radius equals √121 = 11 and the center is (-4,0)
QUESTION 13. As there are missing information in the question, I can't assist. However, you can use the general circle equation (x – h)² + (y – k)² = r² to solve the question.