D. the application of scientific discoveries
Answer:
B. 11110111
Explanation:
Binary representation of number 9 = 00001001
Binary representation of -9 would involve calculating the twos complement representation of 00001001
First we compute the ones complement of this number by reversing the bits.
00001001 => 11110110
Next we calculate the twos complement representation by adding 1 to the ones complement.
11110110+1 = 11110111
So the final representation is 11110111.
Answer:
Because reusing the old passwords possess security threats.
Explanation:
A password can be defined as a string of characters or words or phrases that are used to authenticate the identity of the user. It is also known as passcode and should be kept confidential. A password is used to access constricted systems, applications, etc.
A password or passcode is usually composed of alphabets, numbers, symbols, characters, alphanumeric, or a combination of these.
<u>In the given case, Judy was not able to change her passcode to the previous one because reusing old passwords is prohibited in any sites or systems. A system denies the user to reuse the old passwords for various reasons but most importantly due to security reasons. Though it is said that old passwords can be used after 100 times but seldom someone changes a password that much. All systems care for the security of their users thus they deny reusing old passcodes.</u>