Question

please answers this questions no 9,10??

Answer 1

9)

n^2 -n

n(n-1)

If n is even then n-1 is odd

If n is odd then n-1 is even

We know

Odd ×Even = Even

And every even is divisible by 2

So n(n-1) is divisible by 2 means

n^2-n is divisible by 2. Proved

10)

mx+ny= m^2 -n^2

(m×x ) -( n × -y) = (m×m) - (n×n)

x= m. &. -y= n

So,

x=m

&

y= -n