If 2x + y = 8 and xy = 6 , then find the value of 4x2 + y2 ?

We know that,

If $K+l=n$

then, $K^2+l^2$ = n² – 2 × k × l

If 2x + y = 8

xy = 6

then find the value of 4x² + y²

4x² + y² = 8² – 2 × 2 × 6

4x² + y² = 64 – 24 = 40