7. A distribution centre sends three different types of parcels. One consignment has 6 small, 8 medium and 9 large parcels which cost $173.20 to post. Another consignment has 7 small, 13 medium and 17 large parcels with total postage $291.05. A large parcel costs twice as much to post as a small one. Work out the total cost of posting 3 small parcels, 9 medium parcels and 2 large parcels.

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.

1.based of the diagrams what is the the value of x? 2.how would you verify your answer for x

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.