M is the change in y divided by the change in x. If you take the +1 in x from 0 to 1, and the -6 in y from 1 to -5, M would be -6/1, or -6.
That means that part of the equation y=-6x
B is the y intercept, or when x is 0. That is just +1, so put +1 in the equation.
y=-6x+1 is your answer.