Question

add x^2+2xy+y^2 to the sum of x^2-3y^2 and 2x^2-y^2+9​

Answer 1

${x}^{2} - 3 {y}^{2} + 2 {x}^{2} - {y}^{2} + 9 \\ {x}^{2} + 2 {x}^{2} - 3 {y}^{2} - {y}^{2} + 9 \\ 3 {x}^{2} - 4 {y}^{2} + 9$

$3 {x}^{2} - 4 {y}^{2} + 9 + {x}^{2} + 2xy + {y}^{2} \\ 3 {x}^{2} + {x}^{2} - 4 {y}^{2} + {y}^{2} + 2xy + 9 \\ 4 {x}^{2} - 3 {y}^{2} + 2xy + 9$