Question

If X + 1 upon x = 7 then find x 4 + 1 upon x 4

Answer 1

x+1 / x =7

=> x^2 + 1 = 7x

=> (x^2 + 1)^2 = (7x)^2. {square both side}

=> x^4 + 1 + 2x^2 = 49x^2

=> (x^4 + 1) = 47x^2

=> so now,

x^4 + 1 / x^4

= 47x^2 / x^4

= 47 / x^2.