Answer:
Equation: y=mx+b
sorry for taking so long! :)
AC) y=-1, because it is remaining constant and the slope is zero, the y intercept is -1.
AB) The slope is 1 and the y intercept is 1.
So, y=x+1
BC) The slope is -6. The y intercept is harder to find. You can use this equation however;
y-y(1)=m(x-x(1)
y-5=-6(x-4)
y=-6x+29