If f : R━>R is given by f(x) =x^2 , then f(2) = ?

If f : R━>R is given by f(x) =x² , then f(2) = ?

(A) 6
(B) 4
(C) -4
(D) 8

The answer is: (B) 4
Solution
In the function f(x)=x², replace x by 2. If f(x)=x², then f(2)=(2)²=4