The HCF is the Highest Common Factor of a number in this case 54. This is the highest number times another number which = 54. The HCF for 54 is 18.
The answer is Standard Score (Or Z-Score)

x

1 x 5 = 5
16 x 4 = 64
is the answer
In simplest form the answer would be

because it cant be divided any farther.
Hey There!
To find the blank you have to multiply

*

=
This should be the answer. You can plug in 0 for y to any of the equation to find the x.