Answer: a) 1977060966, b) 146581344.
Step-by-step explanation:
Since we have given that
There are 10 numbers,
There are 26 lower case letters,
There are 26 upper case letters,
Since the first 3 characters have to be digits and next 6 can be upper or lower.
So, a) repetitions are allowed:

b) repetitions are not allowed:

Hence, a) 1977060966, b) 146581344.
Answer:
Permutation is used.
No. of arrangements = 1260
Step-by-step explanation:
Permutation is used for choosing & arrangement of 'r' out of 'n' objects, when sequence is important.
Total no. of alphabets in CORRECT = 7
C is repeated twice, R is repeated twice
So, Total No. of arrangements = <u>7 !</u>
(2!)(2!)
= 5040 / 4
= 1260
EXPLANATION: By definition two lines are said to be parallel when the distance between two lines is same when measured from any point on one line.
However the criteria for intersection is that the distance between two lines should change and eventually should change to zero at intersection point.
Step-by-step explanation:
.
Set up the equation 3x+1= 4x-7 and you’ll get your answer