Well, using your example (untested):
try something like this in your alias section
/formulax //echo $calc(72*3* $1 *79 + 72*2.5* $1 *106 + 72*2.5* $1 *116 + 72*1* $1 *324)
The other thing you could try would be (if it was only one number to be inserted)
/formulax //echo $calc($1 * $1 * $1 * $1 * 72*3*79 + 72*2.5*106 + 72*2.5*116 + 72*1*324)
im sure there are other ways to do this, but this is just an example.
