Verify the identity: 2cosx(sin3x-sinx) = sin4x

Determine the quotient and remainder when (6a3)+11a2-4a-9) is divided by (3a-2) express your answer in the form q(a) + r(a)/d(a)

Is δ pmr similar to δ smn ? if so, which postulate or theorem proves these two triangles are similar?

Atrain leaves little? rock, arkansas, and travels north at 90 kilometers per hour. another train leaves at the same time and travels south at 80 kilometers per hour. how long will it take before they are 680 kilometers? apart?