You are factoring one or more linear expressions (but are not factoring variables).
2.4n+9.6 can be divided by 2.4 and then the result mult. by 2.4:
2.4n+9.6 = 2.4 [ n + 4 ]
Also: -6z+12= 6 [ -z + 2 ] Here I have simplified linear functions but factoring out common constant coefficients (not variables).
the equation 2x-4-1+x would be the answer
Because 2x+x = 3x and -4-1 = 5, the result would be 3x-5