You almost had it right! remember the equation of a circle is
(x - h)^2 + (y - k)^2 = r^2. the center is (h,k) and r is the radius.
(x - 0)^2 + (y - 0)^2 = 5^2
x^2 + y^2 = 25 <<< your answer
hope that helps, God bless!
Set the 2x - 1 equal to 9 then work backwards. 2x - 1 = 9 Nine minus one is eight divided by two is four. X = 4
It is 12495 for sure i took the test and got it right
C = 2 pi r
C = 2 x 3.14 x 5
C = 31.4 yd
A = pi r^2
A = 3.14 x 5^2
A = 3.14 x 25
A = 78.5 yd^2