The like terms are 12 and 5, so you have to subtract 5 from both sides.
12 < x + 5
-5. -5
7 < x
We can just switch it around so x is in the left side.
x > 7
Answer:

Step-by-step explanation:
Complete question

Required
Solve for x
We have:

Collect like terms

Multiply through by 

Make x the subject

Answer:
8.5x10^-5
Step-by-step explanation:
Move the decimal over between the 8 and the 5, it "hops" 5 times. Since it moved over right, make it negative
The ratio of 3/20 is 3:20