What will be the square of x + 1/x, if it is given that x2+1/x2 = 34?
What will be the square of x + 1/x, if it is given that x2+1/x2 = 34?
a. ±7
b. -7
c. ±6
d. -6
e. None of the above
Thanks for asking question on GMAT Section,
Your question was – What will be the square of x + 1/x, if it is given that x2+1/x2 = 34?
Your correct answer is- C
According to the data given in the question, x2+1/x2 = 34
We have to find the value of x+1/x
We have the standard algebraic formula for the square of addition of two numbers as
follows:
(a + b)2 = a2 + 2ab + b2
∴ (a + b)2 – 2ab = a2 + b2
Now substituting a =x and b = 1/x in the above formula, we get,
(x + 1/x)2 = 34 + 2*x*1/x
∴ (x + 1/x)2 = 34 + 2 = 36
Now taking square root on both the sides we get,
x + 1/x = ± 6
Hence, the correct answer is option c.
