Answer:

Step-by-step explanation
The standard equation of a circle centered at origin is 
r = radius of the circle
The circle is passing through the point (0,5)
∴ radius 



∴ The equation of the circle is

Answer:
r=7
Step-by-step explanation:
5r-7=2r+14
add sevento both sides
5r=2r+21
Subtract 2r from both sides.
3r=21
divide both sides by 3
r=7
First you simply have to substitute 2 in replace of all the a's, and -2 in replace of all of the b's
4((2)2+2(-2))
Then you want to follow the order of operations, PEMDAS (Parantheses-Exponent-Multiplication-Division-Addition-Subtraction), and multiply within the parantheses.
4(4+(-4))
Next you will add within the parantheses (So add the 4 and -4 together)
4(0)
Lastly multiply
0
Your answer is 0
Hope this helps!
Answer:
the answer I believe is c
Step-by-step explanation: