Answer:
B 
Step-by-step explanation:
In order to get the same denominator, we need to multiply the second fraction by (b+2) in the numerator and denominator.
We will end up in something like this :
I just timed the second fraction by b+ 2 and then i added them together.
Therefore, we will get 
now factoring the numerator we will end like this

we will then end up with the answer.
Hope this helps.
Answer:
x = 15
Step-by-step explanation:
I have this all put under a photo. Let me know if you need any explanation
Answer:
a)120
b)6.67%
Step-by-step explanation:
Given:
No. of digits given= 6
Digits given= 1,2,3,5,8,9
Number to be formed should be 3-digits, as we have to choose 3 digits from given 6-digits so the no. of combinations will be
6P3= 6!/3!
= 6*5*4*3*2*1/3*2*1
=6*5*4
=120
Now finding the probability that both the first digit and the last digit of the three-digit number are even numbers:
As the first and last digits can only be even
then the form of number can be
a)2n8 or
b)8n2
where n can be 1,3,5 or 9
4*2=8
so there can be 8 three-digit numbers with both the first digit and the last digit even numbers
And probability = 8/120
= 0.0667
=6.67%
The probability that both the first digit and the last digit of the three-digit number are even numbers is 6.67% !