Question

does y=x have a slope of 0?

Answer 1

no,1

Answer 2

Actually it has a slope of 1.

Answer 3

what about y=-x

Answer 4

-1

Answer 5

Slope is basically "rise / run" for the graph.
A slope of 0 means there is no rising to the graph, which means as x gets larger, y stays the same. Note how in y = x, x gets bigger and y is increasing at the exact same rate (it IS x, of course!) So, any graph y = (a constant) makes a slope of 0. y = x is a slope of 1, as x and y increase at the exact same rate. y = -x would have -1 because as x is increasing, y is decreasing in the same rate.

In general, an equation y = mx + b has slope m. Note that m=1 in y = x and m=0 for y = constant.