SSC CGL 2021 PYQ — Question 62

The correct answer is option 2 i.e. 2

Here it is given that,

x⁴ + x²y² + y² =21

On adding  x²y² on both sides we get,

 x⁴ + x²y² + y² +  x²y² - x²y² = 21

(x² + y²)² -  x²y² = 21

(x² + y²)² = 21 + x²y² .................(1)

x² + xy + y² = 3

x² + y² = 3 - xy..................(2)

On putting the value of eq 2 in eq 1 we get,

9 + x²y² - 6xy = 21 + x²y²

-6xy = 12

-xy = 2.