Answer:
c
Step-by-step explanation:
A perfect square trinomial is always in the form
(a+b)(a+b)= 
ie. (x+4)(x+4)= 
You want to multiply together the number of possible choices for each digit in the code.
0-9 is ten possible numbers, since repetitions are allowed (example code 2,2,2,2) there are ten possible choices per digit in the code.
10*10*10*10 = 10,000 four digit coded possible
Answer:
Step-by-step explanation:
the fraction is
right, but notice that the numerator and denominator are both divisible by 16.
64 divided by 16 is 4,
80 divided by 16 is 5.
