Answer:
Probability that first shirt is white and second shirt is gray if first shirt selected is set aside = 
Step-by-step explanation:
Given that
3 white, 2 blue and 5 gray shirts are there.
To find:
Probability that first shirt is white and second shirt is gray if first shirt selected is set aside = ?
Solution:
Here, total number of shirts = 3+2+5 = 10
First of all, let us learn about the formula of an event E:



Now, this shirt is set aside.
So, total number of shirts left are 9 now.

So, the answer is:
Probability that first shirt is white and second shirt is gray if first shirt selected is set aside = 
(x+5) represents each side of a square. Since all sides of a square are equal, we know that all sides are (x+5).
Base x height = (x+5)(x+5)
Which is x^2+10x+25!
Answer:

Step-by-step explanation:
To solve this problem you must know the formula of subtraction of angles for the function cosx.
The formula is:

We can write 30° as: 45° - 15°
Then:

Using the formula for subtraction of angles we have:

Notice that we have achieved the expression shown in the statement
Finally:
