Which expression is equivalent to 3x^2 + 7x - (x+4)^2 - 9?

The following division is being performed using multiplication by the reciprocal find the missing numbers is 5/12 divided by x/3 equals 5/12 times x/10 equals 1/x

Find the volume of the solid obtained by rotating the region enclosed by the curves y=1x and y=7^-x about the x-axis. (use symbolic notation and fractions where needed.) volume =

What is 100,000 times 1/100,000, using the standard method of multiplication? write the answer as 10 to a power.