Find the value of a and b if (x-1) and (x+1) are factors of x⁴+ax³-3x²+2x+b

If x²+y²+z² = xy + yz + zx, then the value of $${3x^4+7y^4+5z^4}\over{5x^2y^2+7y^2z^2+3z^2x^2} $$ is

If  $${3-5x\over 2x}+{3-5y\over 2y}+{3-5z\over 2z}=0$$ then the value of  $${2\over x}+{2\over y}+{2\over z}$$ is:

Find the minimum value of x which the expression  
x³-7x²+11x - 5 ≥ 0.

If x+y=10 and xy=4, then what is the value of x⁴+y⁴=?

If $$ {x=2-2^{1\over 3}+2 ^{2\over 3}}$$, then the value of $$ {x^{3}-6x^{2}+18x+18}$$.

Three positive numbers are in the ratio of 11 : 12 : 15. If the sum of the squares of those numbers is 1960, then the sum of the numbers is