nvijai

A Dodecagon has 12 sides.

Start with this:

225+75-30

The +75 is the 75 points gained, the - 30 is the 30 points lost, and the 225 is her current points.

225 + 75 is 300,

300 - 30 is 270.

Anna finishes off with 270 points.

Maya wins the competition.

nvijai

Just replace n with -2n, like this:

g(-2n)=-2n-4.

Divide by a power of ten to make the number in between 0 and 10. In this case, this is 8.97, and 10^8. Just multily them together.

8.97*10^8

This will be put into a fraction, like this:

15/80

From here, use long division. This would be easy to demonstrate if I had some paper, but I'll just show you the answer:

$${\frac{{\mathtt{15}}}{{\mathtt{80}}}} = {\frac{{\mathtt{3}}}{{\mathtt{16}}}} = {\mathtt{0.187\: \!5}}$$

From here, round to the nearest hundreth.

0.1875-->0.19

19% 

First, input your variables:

3-2*4-(-4)

multiplication first:

3-8-(-4)

Now solve:

-5+4

-1