Solve the equation x to the 2nd power=0.81
a-none of them
b-x=0.9 only!
c-x=0.9 or x= -0.9
d-x= -0.9 only!

answers

\3. yes the presentation (i.e. odd numbers being written as differences of two squares) is possible for all odd natural number however the presentation may not be unique. for example,  57=112−82=292−28257=112−82=292−282.

\4. 2 can't be written as a difference of two squares because 4-1=3 and 1-1=0 and the difference of squares grows to integers larger that 3.

can i get some in proving questions 1 and 2?

the answer is  

c.

90.0π cm^2

hope you got it.