I hope this helps you
Juans weight x
486= 6.x-12
486+12=6x
498=6x
x=83
The given expression
is equal to 144 or 
<em><u>Solution:</u></em>
Given expression is:

We have to evaluate the above given expression
We know that,


Substituting these in above given expression, we get

Also we know that,

Therefore,

Thus the given expression
is equal to 144 or 
I believe the answer is 2