42 is a multiple of 6 with a factor of 6 and 7.
Answer:

Step-by-step explanation:
0.0057
first number
5
then the rest
7
equal
5.7
There's <u>three</u> zeros <u>behind</u> the number 5 which mean it will be -3

final answer

another example and it will be clear
0.0000403
first number
4
then the rest
03
equal
4.03
There's <u>five</u> zeros <u>behind</u> the number 4 which mean it will be -5

final answer

A tautology will have an infinite number of solutions, as it is true for all possible values of the variable by definition.
Example: 3(x+2) = 3x+6
All other linear equations in one variable will have one solution, which may include values that are undefined or indeterminate.
Examples:
... 3x-2 = 7 . . . solution is x=3
... x = 0/0 . . . . solution is an indeterminate number
... x = 1/0 . . . . solution is undefined
6+(-4) is almost like saying 6-4 which is 2
Same for 6+(-6) is just like 6-6 which is 0
Hypothenuse is the longest side
You can see the X is the longest
Solution: A. X