Réponse :

EX1

Développer les expressions

A = 5(2 - x) = 10 - 5 x

B = - 2(- 3 x + 5 y) = 6 x - 10 y

C = 7 x(2 - x) = 14 x - 7 x²

D = - 3 y(8 - 5 y) = - 24 y + 15 y²

EX2

A = 2(x - 3) = 2 x - 6

B = - 3(- 2 + 8 x) = 6 - 24 x

C = 2 x(1 - x) = 2 x - 2 x²

D = - 2 a(- 5 a + 4) = 10 a² - 8 a

EX4

Développe et réduire les expressions

A = 3(x - 1) + 2(2 - x) = 3 x - 3 + 4 - 2 x

   = x + 1

B = 2 - 7(2 - x) = 2 - 14 + 7 x = 7 x - 12

C = - (2 - a) - (- 5 a + 4) = - 2 + a + 5 a - 4 = 6 a - 6 = 6(a - 1)

EX4

Développe et réduire les expressions

A = (x - 1)(2 - y) = 2 x - xy - 2 + y =

B = (x-2)(1+x) = x + x² - 2 - 2 x = x² - x - 2

C = (x - 7)(2 - x) = 2 x - x² - 14 + 7 x = - x² + 9 x - 14  

Explications étape par étape

Bonjour,

Ex1

A) = 5X2-5Xx

= 10-5x

B) =2X3x-2X5y

= 6x-10y

C) = 7xX2-7xXx

= 14x - 7x²

D) = -3yX8+3yX5y

= -24y + 15y²

Ex2:

A) = 2Xx-2X3

= 2x-6

B)= 3X2-3X8x

= 6 - 24x

C) = 2xX1-2xXx

= 2x - 2x²

D) = 2aX5a-2aX4

=10a² - 8a

Ex3:

A)= 3Xx-3X1+2X2-2Xx

=3x-3+4-2x

=1x+1

B)=2-7X2+7Xx

=2-14+7x

=12+7x

C) Je ne sais pas

Ex4

A)xX2-xXy-1X2+1Xy

=2x-xy-2+1y

=1x-2

B)=xX1+xXx-2X1-2Xx

=1x+x²-2-2x

= -1x+x²-2

C) = xX2-xXx-7X2+7Xx

=2x-x²-14+7x

= 9x-x²-14