It is: 7.9-5 = 3.249859185*10-5 in scientific notarion.
Four to the negative 5th power equals 0.0009765625
Seven to the negative 5th power is 0.00005949901
15 to the negative 5th power as a fraction can also be written as 1/15 to the 5th power.
1/-25
.0001
-0.00003
0.000089
0.000049
The same as 42 to the power of 5 but negative
0.000089
1/59049
0.000039