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PRANJUL MISHRA

· started a discussion

· 1 Months ago

misprint in this question please correct it

Question:

If x2 – 3x + 1 = 0, then the value of x2 +x +  1x+ 1x2    is:

Options:
A)

10

B)

2

C)

6

D)

8

Solution:

Ans: (a)

x2 – 3x + 1 = 0

⇒ x2 + 1 = 3x

⇒ x +  1x    = 3(dividing both sides by x)

Squaring both sides,

⇒ x2 +  1x2    + 2 = 9

X2 +  1x2    = 7

∴ x2 +  1x2    + x +  1x   

= 7 + 3 = 10

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