Question

If f(x) = x ^ 2 + 3 , then f(x+y)=?

Answer 1

Answer:

f(x)=x^2+3

f(x+y)=(x+y)^2+3

this is done by replacing x with (x+y)

f(x+y)=x^2+2xy+y^2+3

therefore : f(x+y)= x^2+y^2+2xy+3