Answer:
A. r!
Step-by-step explanation:
Combinations formula:
is the number of different combinations of x objects from a set of n elements, given by the following formula.

Permutations formula:
The number of possible permutations of x elements from a set of n elements is given by the following formula:

Permutation of n things taken r at a time

Combination of n things taken r at a time:

Division:

So the correct answer is:
A. r!
Answer: 7.5
Form your proportion. Let x be the width of QRST.
Length of ABCD Length of QRST
----------------------- = -------------------------
Width of ABCD Width of QRST
8/5 = 12/x
Solve for x by cross-multiplying.
(8)(x) = (12)(5)
8x = 60
x = 7.5
For the first question, all you have to do is substitute the values. for example g(x)=-5x+2 becomes g(-1)=-5(-1)+2
Answer:
x=1−y
2
Step-by-step explanation: