Question

If 2x +3y = 13 and xy = 6,find the value of 8x³ + 27y³ it's urgent plz help ​

Answer 1

Step-by-step explanation:

xy=6

x=6/y

Therefore, 12/y+3y=13

3y²-13y+12=0

3y²-9y-4y+12=0

3y(y-3)-4(y-3)=0

(y-3)(3y-4)=0

y=3 or 4/3

if y=3, then

x=2

if y=4/3, then

x=9/2

There will be two answers. Hope you can solve the rest.

Answer 2

Step-by-step explanation:

xy = 6

x = 6/y (eq 1)

2x + 3y = 13

2(6/y) + 3y = 13 (from eq 1)

12/y + 3y = 13

multiplying y to the whole equation,

12 + 3y² = 13y

3y² - 13y + 12 = 0

3y² - 9y - 4y + 12 = 0

3y (y - 3) -4 (y - 3) = 0

(3y - 4) (y - 3) = 0

3y - 4 = 0

y = 4/3

y - 3 = 0

y = 3

if y = 3,

x = 6/y

x = 6 ÷ 3

x = 2

8x³ + 27y³

= 8 (2)³ + 27 (3)³

= (8 × 8) + (27 × 27)

= 64 + 729

= 793