We have the expression:
(d + e ÷ 8)² - 10f
Where: d = 18, e = 56 and f = 2
Replacing these numbers on the expression above:
(18 + 56 ÷ 8)² - 10×2
We know that:
56 ÷ 8 = 7
10×2 = 20
Then:
(18 + 7)² - 20 = 25² - 20
But: 25² = 625
25² - 20 = 625 - 20
∴ (d + e ÷ 8)² - 10f = 605