y intercept:
It is the point at which the graph of the function crosses the y-axis.
To find the y-intercept of the function. we set x = 0.
In the given table the number of texts reprsents the x variable and charge represents the y variable.
So to determine the y intercept of the given function, the first value of number of text is 0
( that means x=0) and the corresponding y value is $20.
Therefore, the y-intercept is (0 ,20).