Question

from the sum of x squared + y squared and x squared + 2y squared , subtract x squared - y squared +1

Answer 1

${x}^{2} + {y}^{2} + {x}^{2} + 2 {y}^{2} - {x}^{2} + {y}^{2} - 1$
$= {x}^{2} + 4 {y}^{2} - 1$

Answer 2

( x^2 + y^2 + x^2 + 2y^2 ) - x^2 - y^2 + 1
= 2x^2 + 3y^2 - x^2 - y^2 + 1
= x^2 + 2y^2 + 1

Hope this is what you wanted.......