PLEASE HELP!! Part A: A keypad lock asks you to input a four-digit code. If you can choose any digit, 0 through 9, for each of the four digits, how many possible combinations are there?
Part B: Suppose the similar keypad lock asks for a four-digit code but does not allow you to repeat a digit. How many possible combinations are there for this lock?

answer: 12

step-by-step explanation:

because yes

a variable is any characteristics, number, or quantity that can be measured or counted. a variable may also be called a data item. hope i !

, and

for

step-by-step explanation:

we can analyze the pattern at which the terms increase. let us denote , , , so that we can call

note the following:

the pattern: to get the next term value, we just add the next term number (e.g. 1st, 2nd, to the previous term value (term values are the given numbers in the question, 1, 3, 6, 10, 15,

from , to get to , we add

from , to get to , we add

etc.

we need to form a recursive formula, a formula that has the next term as a function of the previous term. so a possible recursive formula can be

, and for

sas (side angle side)

aa (angle angle)

sss(side side side)

sas find two sides with an angle in between

aa is finding two angles and the third will add up to 180

sss find all sides

step-by-step explanation: