f(x)=x²+2x+1
f( (2a-3)/5)=(2a-3)²/25 + 2( (2a-3) / 5) + 1
=(4a²-12a+9)/25 + (4a-6)/5 + 1
=(4a²-12a+9+20a-30+25)/ 25
=(4a²+8a+4) / 25
=4(a²+2a+1) / 25
=4(a+1)² / 25
(2(a+1) / 5)²
f(x)=x²+2x+1
f(1/a)=1/a² + 2/a + 1
= 1/a² + 2a/a² + a²/a²
=(a²+2a+1)/a²
=(a+1)²/a²
=( (a+1) / a )²
