Not a complete question please send a picture of your problem.
Rearrange the like terms first.
1. 4x+3x+9=30
add the like terms
2. 7x+9=30
move the 9 to the other side.
3. 7x=30-9
subtract them
4. 7x=21
divide bothers sides by 7
5.

which it will end with the result of
x=3
0.63% of 100 =
0.63
I typed this part to make the question 20 characters long
30 % like pineapple
15 % like banana
The percentage is of 100%
30/100 like pineapple and 15/100 like banana = 15 % more students favor pineapple