bonjour

il suffit que tu appliques :  k (a+b) = k*a + k*b           * = multiplié par..

4 + (x-3) x 5

= 4 + 5 (x-3)

= 4 + 5*x + 5*(-3)

= 4 + 5x - 15 = 5x - 11

2x (x+1) - 1

= 2x*x + 2x*1 - 1

= 2x² + 2x - 1

- (4-x) x 2

= -2 (4-x)

= -2*4 + (-2)*(-x)

= - 8 + 2x = 2x - 8

tu continues :)