Answer:
18
Step-by-step explanation:
first find the total 27min then you find the amount he already practiced 9min. now you have everything you need. if you here, how many more, it usually means subtract. so 27-9=D is the formulated answer
5x + 10
I did the math and checked. :)
Your photo wont show up
is the boundary of the triangle 
, then by Green's theorem
