Tikur anbesa hosepital purchased a special X-ray machine for its operating room the machine which coset Birr 311.560 was expected to laset ten years with an estimated residual value of birr 31.560 after tow years of operation and depreciation charges using the straingh line rate it became evident that the X-ray machine would remain the same given this information determine​

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.

An airplane travels at an unknown elevation before it descends 3 miles to an elevation of 15 miles. find the elevation of the plane before its descen.

Evaluate the function , when d = {9, 15, 30}. r = {5, 7, 12} r = {6, 10, 15} r = {6, 10, 20} r = {5, 12, 20}