Question

2 1f x^ 2 + 4 x^ 2 =5, find the value of x ^ 3 + 8/(x ^ 3)​

Answer 1

Answer:

9

Step-by-step explanation:

x²+4/x²=5

Adding 4 to both sides

x²+4/x²+4=9

(x+2/x)²=9

x+2/x=√9=3...(i)

(x+2/x)³=27 (cubing both sides)

x³+8/x³+3×x×2/x(x+2/x)

x³+8/x³+6×3 (from i)

x³+8/x³+18=27

x³+8/x³=9