659. What is the value of the expression ab- 30 when a =-4, b = 5 and c=-3? a. -29 b. -26 C. -11 d. 20 please help me.

Agraph of a trapezoid can have diagonals with slopes that are negative reciprocals and two pairs of adjacent sides that are congruent, true or false, and why

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.

Cody started biking to the park traveling 15 mph, after some time the bike got a flat so cody walked the rest of the way, traveling 4 mph. if the total trip to the park took 6 hours and it was 46 miles away, how long did cody travel at each speed? solve using rate times time= distance