Please help with these two questions

The surface area (sa) of a cube with a as the length of each of its sides is given by the formula . if the surface area is known, how can you rewrite the formula to find its side?

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25

Given: jk ||lm prove: _2 = 27 statement justification 1. jk ||lm 1. given 2.26 = 27 3.22 = 26 2. 3. 4. _2 = 27 4. corresponding angles theorem transitive property of equality vertical angles theorem substitution property of equality