Answer:

Step-by-step explanation:
When adding rational numbers, if the denominator is the same you simply keep the denominator (bottom of fraction) as it is and apply the operation given to the numerator ( top of fraction )
So we have 
==> remove parenthesis and apply signs

==> simplify numerator by combining like terms

and we are done!
Note:
like terms are terms with the same variable and exponent
An example of like terms are 6x^7 and 3x^7 as they have x as a variable and a power of 7
The like terms being combined here were (6x² and 4x²) and (5 and -2)
Answer: The loser's card shows 6.
Explanation: Let's start by naming the first student A and the second student B.
Since the product of A and B are either 12, 15, or 18, let's list every single possibility, the first number being A's number and the second number being B's number.
1 12
1 15
1 18
2 6
2 9
3 4
3 5
3 6
4 3
5 3
6 2
6 3
9 2
12 1
15 1
18 1
Now, the information says that A doesn't know what B has, so we can immediately cross off all of the combinations that have the integer appearing once and once ONLY off, because if it happened once only, A would know of it straight away. Now, our sample space becomes much smaller.
1 12
1 15
1 18
2 6
2 9
3 4
3 5
3 6
6 2
6 3
Using this same logic, we know that we can cross off all of the digits that occur only once in B's column.
2 6
3 6
Now, A definitely knows what number B has because there is only one number left in B. Hence, we can conclude that the loser, B, has the integer 6.
Answer:
4
Step-by-step explanation:

Answer:
0.292
Step-by-step explanation:
Combinations can be used to solve the following problem.
We are choosing 5 widgets from 25 = ²⁵C₅
We want to select zero widgets from defective widgets = ⁵C₀
From the 20 non-defective widgets we want to select 5 = ²⁰C₅
So the probability is:
P = ( ⁵C₀ * ²⁰C₅) / ²⁰C₅
P = (1 * 15504) / 53130
= 15504/ 53130
=0.292 ..
F(n)=3n-2
Plug in 2 for n. f(2)=3(2)-2=4