if x⁴+y⁴+x²y²=21 and x²+y²-xy=7, then what is the value of  $${x\over y}+{y\over x}=?$$

What is the value of a²+b²+c²-2ab-2bc+2ca?

if $${{x^{24}+1}\over x^{12}}=7$$ then the value of   $${{x^{72}+1}\over x^{36}}$$ is

if $$x-{1\over 5},x≠0,$$ then what is the value of $${x^6+3x^3-1}\over x^6-8x^3-1$$=?

If x + y + 3 = 0 , then find the value of x³+y³-9xy+9.

If x = 2 - 2^1/3 + 2^2/3, then the value of x³– 6x² + 18x + 18 is

Given that x³ + y³ = 72 and xy = 6 with x > y. Then the value of (x – y) is

if $${{5x-7}\over 3}+2={{4x-3}\over 4}+4x$$, then the value of (8x+5) is