Vicki has a 50 inch roll of ribbon. she uses 3 feet of the ribbon to wrap a gift. how many inches of ribbon does she have left?

What's the difference between: x≥0 and nonnegative integer. ?

The lines shown below are parallel. if the green line has a slope of -1, what is the slope of the red line?

In the figure below, ∠dec ≅ ∠dce, ∠b ≅ ∠f, and segment df is congruent to segment bd. point c is the point of intersection between segment ag and segment bd, while point e is the point of intersection between segment ag and segment df. the figure shows a polygon comprised of three triangles, abc, dec, and gfe. prove δabc ≅ δgfe.