Need with number 19 and 20 . all a b c question

Compare these two waves: the blue and orange waves have the same pitch, but the blue wave is louder. the blue and orange waves have the same volume, but the blue wave has a higher pitch. the orange wave has a higher pitch, but the blue wave is louder. the blue wave has a higher pitch, but the orange wave is louder.

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Abus travels 36 miles in 45 minutes. enter the number of miles the bus travels in 60 minutes at this rate.