Respuesta :

27 y³ - 343 = ???
27 y³ = 3y * 3y * 3y
343 = 7 * 7 * 7

∴ 27y³ - 343 = (3y-7)(9y² + 21y + 49 )
The correct answer is the first option.
cube root of -343 is -7
cube of 27 is 3
(3y - 7)^3