Given the function f (x) = x2 + 3x + 1, then f (x + 1) is equal to

Given the function f (x) = x2 + 3x + 1, then f (x + 1) is equal to

f(x)=x²+3x+1
f(x+1)=(x+1)²+3(x+1)+1
=x²+2x+1+3x+3+1
=x²+5x+5