Answer:
x=8
Step-by-step explanation:
4.6x-9.3=27.5
+9.3 +9.3
-------------------------
4.6x=35.8
4.6x/4.6 35.8/4.6
x=8
Assuming 13 is the radius the answer is 81.64cm
The quadratic formula is -b plus minus the square root of b^2-4ac all over 2a.
Here, a=1, b=13, and c=30.
The only option that fills in the values correctly is D
