Algebra: A Combined Approach (4th Edition)

6$x^{2}$ -2xy + 19$y^{2}$
( $x^{2}$ + 2xy - $y^{2}$ )+ ( 5$x^{2}$ -4xy + 20$y^{2}$ ) $x^{2}$ + 2xy - $y^{2}$ + 5$x^{2}$ -4xy + 20$y^{2}$ $x^{2}$ + 5$x^{2}$ + 2xy -4xy - $y^{2}$+ 20$y^{2}$ ) combine like terms 6$x^{2}$ -2xy + 19$y^{2}$ simplify