Calculate the mean: 5, 4, 8, 12, 15

Find the value of x for which line a is parallel to line b

Aboard 60 in. long is cut two parts so that the longer piece is 5 times the shorter. what are the length of the two pieces?

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b