Do question 9 9 Factorise x2 + 1x2 - 7 x-1x + 8[Hint : Put - Maths - Factorisation

Question

Do question 9

9     F a c t o r i s e     x 2   +  
1 x 2   -   7   x - 1 x   +   8 [ H i n t
  :   P u t   x     -   1 x   =
  y   ]

Sanjari Kalantri · Accepted Answer

Dear Student,

We have: x2 + 1x2 - 7x - 1x + 8Let x - 1x = yThen, x - 1x2 = y2 ⇒ x2 + 1x2 - 2x1x = y2 ⇒ x2 + 1x2 = y2 + 2∴ x2 + 1x2 - 7x - 1x + 8= y2 + 2 - 7y + 8= y2 - 7y + 10= y2 - 5y - 2y + 10= yy - 5 - 2y - 5= y - 5y - 2= x - 1x - 5x - 1x - 2                             ∵ x - 1x = y

Do question 9 9 . F a c t o r i s e x 2 + 1 x 2 - 7 x - 1 x + 8 [ H i n t : P u t x - 1 x = y ]

Do question 9

$9 . F a c t o r i s e x^{2} + \frac{1}{x^{2}} - 7 (x - \frac{1}{x}) + 8 [H i n t : P u t x - \frac{1}{x} = y]$