We are to determine if the given are differences of perfect cubes and in order to do so, we simply have to calculate for the cube root of the terms in the given.
(a) 9a³ - 27 = ((∛9)a)³ - 3³ ; NO
(b) 125a¹² - 72 = (5a⁴)³ - (∛72)³ ; NO
(c) 216a⁶ - 27y³ = (6a²)³ - (3y)³ ; YES
(d) 8a¹⁵ - 27 = (2a⁵)³ - (3)³ ; YES
(e) 225a³ - 216 = (15a)³ - (6)³ ; YES
Therefore, the answers are the third, fourth, and fifth choices.
I think you just subtract 59 and 11 but i could be wrong
if you mean the triangle one, it's 25cm
8 + 6.2 + 4a - 9a
(8 + 6.2) + (4 - 9)a
14.2 - 5a is your answer.
