Développer : A. 7(x-3) B. 5(-7+x)

7(x-3) = 7x x + 7x (-3) = 7x -21

5(-7+x) = 5 x (-7) + 5 x x = -35 + 5x

Bonsoir,

A = 7 ( x - 3 ) 
= 7 * x + 7 * ( - 3 )
= 7x - 21

B = 5 ( - 7 + x )
= 5 * ( - 7 ) + 5 * x
= - 35 + 5x

Si tu as des questions n'hésite pas =)