I don’t see the problems you want me to solve. Sorry
A. 3 times 10^4
90000000 divided by 3000 is 30000 which happens to be equal to 3 times 10^4
If you want to learn how to do this just take your whole number ex: 3 and put 10^6 and you will have 3 followed by 6 zeros. The ^ is just how many zeros will follow your whole number at first.
The angle that is next to 9x should be 180 - 9x because it is a straight angle.
Since there are 180 degrees in an angle we can add up the values to 180 and solve for x.
180- 9x + 5x + 9 + x = 180
-3x = -9
x = 3
Hope this helped!