If you know that the equation for a line has slope, and that it passes through the pointm, then it's equatoin is:(x1, y1)

or rearranging:

So here you have:

y-8 = 17.77(x-1)

Which you can rearrange into y = mx+b form:

y = 17.77(x-1) + 8.

y = 17.77x -9.77

The y-intercept of the line is therefore: -9.77