Question

If x= 5−x 1 ​ and x  =5, find : x 3 + x 3 1 ​ .​

Answer 1

Answer:

Step-by-step explanation:

answer

Answer 2

Formula to be used : (a+b)

3

=a 3 +b 3 +3ab(a+b)x+ x1 =5

Cubing on both sides:

→(x+ x1 ) 3 =5 3

→x 3 + x 3 1 +3⋅x⋅ x1

⋅(x+ x1 )=125

→x 3+ x 31 +15=125

→x 3+ x 3 1 =125−15=110