A scuba diver dove from the surface of the ocean to an elevation of -59 9/10 feet at a rate of -12.6 feet per minute. After spending 10.5 minutes at that elevation, the diver ascended to an elevation of -8 9/10 feet. The total time for the dive so far was 17 1/8 minutes. What was the rate of change in the diver's elevation during the ascent? Round your answer to the nearest hundredth. The rate of change of the diver's elevation was ft/min.

he used the algebra tiles correctly.

step-by-step explanation:

given : 3x(2x-1)

solution :

since he used algebra tiles .

armando's solution is the same in the solution shown in figure

as he distributed 2x into x and x and wrote them vertically

and also write   -1 vertically

and 3x into x and x and x and wrote it horizontally

performing the multiplication in the algebra tiles we get

and solving the given expression :

3x(2x-1)

since solving the expression using tiles   and solving the expression algebraically we get the same answer

thus   we can choose the first statement as the answer to this problem which is "he used the algebra tiles correctly".