Answer:
Mr.Lin's present age is 30 years now. His son is 8 years old now.
Step-by-step explanation:
Let L = Mr.Lin's present age,
S = his son's present age.
First equation is
L + S = 38. (1)
The second equation is
L + 3 = 3*(S+3) (2) ("In three years' time, Mr.Lin will be three times as old as his son.")
From (1), express S = 38-L and substitute it into (2). You will get
L + 3 = 3*((38-L)+3), or
L + 3 = 114 - 3L + 9,
4L = 114 + 9 - 3,
4L = 120,
L = 30.
Answer: 
Step-by-step explanation:
Given the following inequality:

You need to solve for "x" in order to find the solution.
The steps are:
1. Add
to both sides of the inequality:

2. Add
to both sides:

3. Divide both sides by
:

Notice that "x" is less than 8. This indicates that 8 is not included in the solution and you must use parentheses.
The solution in Interval notation is:

Answer:
5,7,3,2
Step-by-step explanation:
It's pretty simple: a prime number is a number that can *only* be divided by the number 1 and it's own.
I just checked all the numbers from 1 to 10 in order to solve this problem.
If you have any questions about the way I solved it, don't hesitate to ask!
Answer:
three hundred and eight five twenty sevenths