If a varies directly as b, and a = 28 when b = 7, find b when a = 5.

What is the number 321,000,000 in scientific notation? also what is the number? ?

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

240 seventh graders and two-thirds of the students participate in after-school activities how many students participate in after-school activities