what is the slope-intercept of:y=x-1
There is no such noun as slope-intercept. Slope and intercept are two different things. Sometimes slope-intercept is used as an adjective to describe a way of writing an equation.
In the standard-format linear equation,
y = mx + b ,
m is the slope and b is the y-axis intercept (where x = 0). Usually b is called the "y-intercept". There also an x-intercept, where y = 0.
Your equation is already in the standard format. In your case, the ooefficient of x is 1 (Coefficients that equal 1 are not written down; you just write "x" instead of 1x) You should now be able to guess what b is. It is the constant term in the equation.