First you can find the rate of change to be 4.25. Then you can subtract 4.25 repeatedly until you get to an output with an input of zero. The initial value is the output when the input is zero. The initial value after subtracting 4.25 three times is 29.50.
Because the inputs go by 2, the rate of change is half the difference of the outputs, or 4.25. Subtract 4.25 repeatedly 3 times to get to an output with an input of 0. Calculate 42.25 – (3 x 4.25). The initial value is 29.50.
