Question

2. If (4a + 3b) = 10 and ab = 2, find the value of 64 a ^3+ 27 b^3).​

Answer 1

Answer: 980

Step-by-step explanation:

(4a + 3b) = 10 and ab = 2, find the value of 64 a ^3+ 27 b^3)= (4a)^3+ (3b)^3

Also, a^3+b^3=+a+b) (a^2+b^2-ab)

So, (4a)^3+ (3b)^3= (4a+3b) [ (4a)^2+ (3b)^2+ 4a×3b) ]

Using, a^2+b^2+ab= (a+b)^2-ab

So, (4a)^3+ (3b)^3= 10 × [ (4a+3b)^2-ab]

= 10 × [(10)^2- 2]

= 10× [ 100-2]= 10 × 98= 980