What is -y=x+1 in gradient intercept form

That's already in gradient-intercept form, EXCEPT that we typically write such an equation with y positive.

So we'd geet   y = -x - 1   (answer)

Note that "gradient" means "slope" here.  The slope is -1 and the y-intercept is also -1.

Ithink the answer is: it is likely.