Can someone me for question 9, 10, 11, 12, and 13?

i use my brain for prombles like this maybe you could try it

step-by-step explanation:

нιѕ яαтє ιѕ 1/4 σя .25 ριєѕ ρєя мιиυтє

нσρє ι ¢συℓ∂ нєℓρ уσυ.

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?