An identity function has one output value for each input value.
G is an identity function.
To find its equation apply the slope-intercept form:
y=mx +b
Where:
m= slope ( rise / run)
b= y-intercept ( where the function crosses the y axis)
By looking at the graph we can see that it crosses (0,0) so, b= 0.
And for every unit to right along the x-axis, it goes up by 1 unit along the y axis.
So, m= 1/1 = 1
Equation:
y = x