Multiply -8/9 and -18/25 then simplify

Which equation can be used to measure the density of water in a spherical water tank? let w represent the number of water particles within the region.

Would greatly appreciate these 3 answers

The first and second steps to solve the equation 3x/5 + 5 = 20.are shown below 3x/5 + 5 - 5 = 20 - 5 3x/5 (5/3) = 15 (5/3)a.addition property of equality b.subtraction property of equalityc.multiplication property of equalityd.division property of equality