Can u solve 12 thru 14 questions step by step and show your work and how you got the answer

Using inductive reasoning, what is the next two numbers in this set? 1,-7,13,-19 i got the numbers 14,-26 is that right?

If each bricks costs and he can only buy one brick how much will it cost him to get the material to put around the outside of his garden?

When you find the area of a triangle do you use in. or in2