Question

X²+1/x²=7
Then x³+1/x³is equal to

Answer 1

Answer:

x³ + 1/x³ = 18

Step-by-step explanation:

(x +1/x)² = x² + 1/x² +2

x+1/x= √9

x+ 1/x = 3

(x+1/x)³ = x³ + 1/x³ + 3(x+1/x)

3³ = x³ + 1/x³ + 3 *3

x³ + 1/x³ = 27-9 = 18