Solution :
From the given graph the x-intercept is 2 and y-intercept is -1 .
So, equation of line in intercept form is :
[tex]\dfrac{x}{2} + \dfrac{y}{-1} = 1\\\\x - 2y = 2[/tex]
[tex]y = \dfrac{x-2}{2}[/tex]
Now, putting x = 4 in above equation, we get :
[tex]y = \dfrac{4-2}{2}\\\\y = 1[/tex]
Therefore, the value of function at x =4 is 1 .