Suppose 3 -2a+b

(I already got -2 and -3 as answers, and it was wrong.) I need this answer quickly.

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.

Idon’t understand this.. will someone ? will mark brainliest along with 20 points.

Name the most appropriate metric unit for each measurement