Question

1- CALCULE :
a) (7x+4y) * ( 7x-4y ) =
b) (9+5y)² = 
c) (12-2x)² = 
d) (14x+2y) * (14x-2y) =
e) (20x+10y)² =
f) (20x-10y)² =

Pf me ajudem , vale nota , obrigado ;) 

Answer 1

  

1- CALCULE :
a) (7x+4y) * ( 7x-4y ) = 49x^2 - 16^2

b) (9+5y)² =  81 + 90y + 25y^2

c) (12-2x)² =   144 - 48x + 4x^2

d) (14x+2y) * (14x-2y) = 196 - 4y^2

e) (20x+10y)² = 400x^2 + 400xy+ 100y^2  

f) (20x-10y)² = 400x^2 - 400xy+ 100y^2 

Answer 2

a) (7x+4y) * ( 7x-4y ) 
49x² - 28xy + 28xy - 16y²         elimina - 28xy + 28xy
49x²  - 16y²

b) (9+5y)² = 
(9 + 5y).(9 + 5y)
81 + 45y + 45y + 25y²
81 + 90y + 25y²  


c) (12-2x)² 
(12 - 2x).(12 - 2x)
144 - 24x - 24x + 4x²
144 - 48x + 4x²


d) (14x+2y) * (14x-2y) =
196x² - 28xy + 28xy - 4y²       cancela  - 28xy + 28xy
196x² - 4y²



e) (20x+10y)² =
(20x + 10y).(20x + 10y)
400x² + 200xy + 200xy + 100y²
400x² + 400xy + 100y²


f) (20x-10y)² =
(20x - 10y).(20x - 10y)
400x² - 200xy - 200xy + 100y²
400x² - 400xy + 100y²