Question

(–5.7 • 2) • 8 = –5.7 • (2 • x)

Answer 1

(-11.4) · 8 = -5.7 · (2 · x)
-91.2 = -5.7 · (2 · x)
16 = 2 · x
x = 8

Answer 2

It's 8 because of the commutative property.