1. Given x + 1 / x = 4, then the value of X & sup2; + 1 / X & sup2; is () A. 12 b.1/2 c.16 D. uncertain 2. Given x = 2009, y = 2010, then (x + y) · X & sup2; + Y & sup2 / / X quartic - y quartic equals () 3. If x / 3 = Y / 4 = Z / 7, then the value of 3x + y + Z / y is ()

1. Given x + 1 / x = 4, then the value of X & sup2; + 1 / X & sup2; is () A. 12 b.1/2 c.16 D. uncertain 2. Given x = 2009, y = 2010, then (x + y) · X & sup2; + Y & sup2 / / X quartic - y quartic equals () 3. If x / 3 = Y / 4 = Z / 7, then the value of 3x + y + Z / y is ()

1.(x + 1/x)^2 = x^2 + 2 + 1/x^2 = 16
So the answer is: 14
2. The original formula = (x + y) (x ^ 2 + y ^ 2) / (x ^ 2 + y ^ 2) (x ^ 2-y ^ 2) = 1 / (X-Y) = - 1
3. Suppose x = 3T, y = 4T, z = 7T (satisfy the condition)
Substituting = (3 * 3T + 4T + 7T) / (4T) = 5