Question

X cube + 8 y cube + y - 216 when x is equal to 2 y + 6

Answer 1

Answer:

16y³ + 72y² + 217y

Step-by-step explanation:

x = 2y+6

x³ + 8y³ + y - 216

= (2y+6)³ + 8y³ + y - 216

= 8y³+ 72y²+ 216y + 216 +8y³ + y - 216   (∵ (a+b)³ = a³ + 3a²b+3ab²+ b³)

= 16y³ + 72y² + 217y