Answer:
We are given with a function , 
To find graph for the f(x).
First we simplify the given function.
Consider,


using identity, a² - b² = ( a - b )( a + b )

f(x) = 2x + 4
Obtained function represent a straight line whose slope is 2 and y-intercept is 4
Let say, y = 2x + 4
then when x = 0 we get, y = 4
when y = 0 we get, x = -2
So we get a graph of function that is a line passing through ( 0 , 4 ) and
( -2 , 0 )