11 more than five of a certain number would be written as 5x+11 and it is (means equal to) twenty more than two times that number, which would be 2x+20. So the equation would be
5x+11=2x+20
-2x -2x (get the x's on one side)
3x+11=20
-11 -11 (get the numbers on one side)
3x=9
/3 /3 (divide by 3, so you can get the x by itself)
X=3 (the number is 3)
0.00035 cm = 3500 nm
1 cm = 10000000 nm
2 * x/100 = 8
x/100 = 4
x = 400
400%
