Answer:

Step-by-step explanation:
By using the formula:-

where, (h,k) is the center and r is the radius
Answer I think the first one
Step-by-step explanation:Hope this helps
Answer:
Step-by-step explanation:
hello :
the system is : x+ y =4 ...(*)
2x - y = -1...(**)
add(*) and (**) : 3x=3 so : x=1
put this value into (*) : 1+y=4 so : y=3
one solution : (1 , 3)