The last side would be 10
Hey there!
#1 ⬇️
6 × 6 × 6 × 6 × 6
6 × 6 = 36
36 × 36 × 6
36 × 36 = 1,296
1296 × 6 = 7,776
Answer: 7,776 ☑️
#2 ⬇️
3 × 3 × 3 × 3
3 × 3 = 9
9 × 9 = 81
Answer: 81 ☑️
Good luck on your assignment and enjoy your day!
~LoveYourselfFirst:)

1) Let's simplify those expressions making use of exponents rules:

Note that the exponent outside the parenthesis is 'distributed' over each term inside.
2) Similarly for the second expression we can state that: