Question

If,x=9-4√5,findvthe value of x square+1/x square

Answer 1

322

Step-by-step explanation:

x=9-4 root5

1/x= 1/9-4 root5 × 9+4 root5/ 9+4 root5

=9+4 root5/ 81 - 80

=9+4 root5

now, x² +1/x²

=(9-4root5)² + (9+4 root5)²

=81+80-72root5 + 81+80+72root5

=322

Answer 2

Answer:

x² + 1/x² = 322

Step-by-step explanation:

Given : If x=9-4√5

To find : The value of x² + 1/x²

Solution :

First we find, 1/x

Substitute x = 9 - 4√5

1/x = 1/9 - 4√5

1/x = 1/9 - 4√5 × 9 + 4√5/9 + 4√5

1/x = 9 + 4√5 / (9)² - (4√5)²

1/x = 9 + 4√5 / 81 - 80

1/x = 9 + 4√5

Now, substitute in x² + 1/x²

x2 + 1/x² = (9 - 4√5) + (9 + 4√5)

=81 + 80 - 72√ + 81 + 80 - 72√

=161 + 161

=322

Therefore, x² + 1/x² = 322

HEY MATE IF IT'S HELPFUL TO YOU PLS MARK ME AS BRINLIEST...