Answer:

Step-by-step explanation:
A quadratic expresion is of the form

where

The give options are:




From the given options, the only expression which is quadratic is

where a =5, b=9 and c=-1
Therefore the correct choice is the second option.
81 is a composite number because it is the only number in the list that is not prime and is divisible by smaller primes.
Answer:
Step-by-step explanation:
r =5sin i
r=5 cos i
divide
tan i=1=tan (π/4),tan(π+π/4)
or tan i=tan (π/4),tan(5π/4)
or tan i=tan (2n π+π/4),tan (2nπ+5π/4)
or tan i=tan ((8n+1)π/4),tan((8n+5)π/4)
i=(8n+1)π/4,(8n+5)π/4
where n is an integer.
so we get infinite points of intersection.
The area of a circle is A= pi*r^2
So we get
Area= 3.14* 4^2= 50.24ft^2
7.54 is the square root of 57.