Simplify 27x^2-5y^2+(12y^2-14x^2)

$27 x^{2} - 5 y^{2} + (12 y^{2} - 14 x^{2})$

Remove parentheses.

$27 x^{2} - 5 y^{2} + 12 y^{2} - 14 x^{2}$

Subtract $14 x^{2}$ from $27 x^{2}$ .

$13 x^{2} - 5 y^{2} + 12 y^{2}$

Add $- 5 y^{2}$ and $12 y^{2}$ .

$13 x^{2} + 7 y^{2}$