Question

) Simplifique as expressões:
a) (x + y)2
– x
2
– y
2
=
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=0
x^2 + 2*x*y + y^2 - x^2 - y^2
2xy
b) (x + 2)(x – 7) + (x – 5)(x + 3) =0
x^2 -7x +2x -14 + x^2 +3x -5x -15
(x^2 + x^2) + (-7x + 2x + 3x - 5x) + (-14 -15)
2x^2 -7x - 29
c) (2x – y)^2 - 4x(x – y) =0
4x^2 - 2*2x*y + y ^2 -4x^2 -4x*(-y)
4x^2 - 4xy + y^2 -4x^2 +4xy
y^2
Lembrando que,
(x + y)^2 = x^2 + 2xy + y^2
(x - y)^2 = x^2 - 2xy + y^2