Question

if 2x+3y=12 and xy=6. find the value of 8x cube+27y cube​

Answer 1

Answer:

1755 or 432

Step-by-step explanation:

x = 6/y

Also, 2x + 3y = 12

⇒ 2(6/y) + 3y = 12

⇒ 12 + 3y² = 12y

⇒3y² - 12y + 12 = 0

⇒ 3y² - 6y - 6y + 12 = 0

⇒ 3y(y - 2) - 6(y - 2) = 0

⇒ y = 2, 6

Now, x = 3 , 1

Put y = 2 , x = 3 in given equation

⇒ 8*3*3*3 + 27*2*2*2 = 216 + 216 = 432

Put y = 6 , x = 1 in given equation

⇒ 8*6*6*6 + 27*1*1*1 = 1726 + 27 = 1755