So, plug in what you're given and solve
x is -2
(3x) * 9
(3 (-2)) * 9
-6 * 9
-54
then
27(-2)
-54
For the first it's the same
for the second
x is 0
(3x) * 9
(3 (0)) * 9
0 * 9
0
27x
27(0)
0
For the second it's the same
x is 4
(3x) * 9
(3(4)) * 9
12 * 9
108
27x
27(4)
108
The given expressions are equivalent. This was proved in the diagram.
Hope this helps :)