Question 1052802
<pre>

log(A) means the power to which 10 must be raised to give A.

log10^12 = 12 because the power to which 10 must be raised
in order to get 10 raised to the 12th power is 12.

log10^9 = 9 because the power to which 10 must be raised
in order to get 10 raised to the 9th power is 9.

log10^0.4 = 0.4 because the power to which 10 must be raised
in order to get 10 raised to the 0.4th power is 0.4.

[The above requires the same reasoning as 
<i>
"The city to which you must be in -- 
in order to be in Chicago -- is Chicago."</i>  :)]

So

If x=log10^12,y=log4^2×log10^9 and z=log10^0.4 find x-y-z

becomes:

If x=12,y=log4^2×9 and z=0.4 find x-y-z

So x-y-z = 12-9×log4^2-0.4 = 11.6-9×log4^2 = ll.6-9×log16 = 

11.6-9×1.204119983 = 0.762920153.

Edwin</pre>