Question

Simplifique
as expressões.


a) (x+y)2–x2-y2


b) (x+2)(x-7)+(x-5)(x+3)


c) (2x-y)2-4x(x-y)

Answer 1

a) $(x+y)^{2}-x^{2}-y^{2} \\\\ x^{2}+2xy+y^{2}-x^{2}-y^{2} \\\\ \not{x}^{2}+2xy+\not{y}^{2}\not{-x}}^{2}\not{-y}^{2} \\\\ \boxed{\boxed{2xy}}$


b) $(x+2) \cdot (x-7)+(x-5) \cdot (x+3) \\\\ (x^{2}-7x+2x-14)+(x^{2}+3x-5x-15) \\\\ \boxed{\boxed{2x^{2}-7x-19}}$


c) $(2x-y)^{2}-4x \cdot (x-y) \\\\ 4x^{2}-4xy+y^{2}-4x^{2}+4xy \\\\ \not{4x}^{2}\not{-4xy}+y^{2}\not{-4x}^{2}+\not{4xy} \\\\ \boxed{\boxed{y^{2}}}$