Does anyone know how to solve this? 4+9×2÷3−1

Which statement best describes how private industry decides where to spend the money on research and development

Which of the following situations is impossible? a) an object has velocity directed east and acceleration directed east. b) an object has zero velocity but non-zero acceleration. c) an object has constant non-zero velocity and changing acceleration. d) an object has velocity directed east and acceleration directed west. e) an object has constant non-zero acceleration and changing velocity.

At what time will the interfering waves have an amplitudeof zero?