Sagot :

Vins

bonsoir

( 7 x + 1 )² - 2 ( x + 4 x²)

= 49 x² + 14 x + 1 - 2 x - 8 x²

=  41 x² + 12 x + 1

( x - √5) ² = x² -  2 x √5 + 5

( x /7 - 2/3) ( x + 7  + 2 /3 ) =  x² /49 - 4/ 9

( 3 x + 2 )² - 100 = ( 3 x + 2 - 10 ) ( 3 x + 2  + 10 ) = ( 3 x - 8 ) ( 3 x + 12 )

( 2 x + 7 ) ( x - 5 + 2 x - 1 ) = ( 2 x + 7 ) (  3 x - 6 )

(  7 x - 3 ) ( x + 2 ) + 1 ( x + 2 )

= ( x + 2 ) ( 7 x - 3 + 1 )

= ( x + 2 ) ( 7 x - 2 )

PetiteKyojo
Bonsoir,

1) a) (7x+1)^2-2(x+4x)^2
49x^2+14x+1-2x-8x^2
=41x^2+12x+1

b) (x-V5)^2
x^2-2xV5+V5^2
=x^2-2V5x+5

c)(x/7-2/3)(x/7+2/3)
(x/7)^2-(2/3)^2
=x^2/49-4/9

2) a) (3x+2)^2
(3x+2-10) X (3x+2+10)
(3x-8)(3x+12)
(3x-8) X 3 (x+4)
=3(3x-8) X (x+4)

b)(2x+7)(x-5)+(2x+7)(2x-1)
(2x+7) X (x-5+2x-1)
(2x+7) X (3x-6)
(2x+7) X3 (x-2)
=3(2x+7) X (x-2)

c)(7x-3)(x+2)+x+2
(x+2) X (7x-3+1)
=(x+2) X (7x-2)