bjr
ton cours te dit que :
k (a + b) = k * a + k * b * = fois - multiplié par
donc
A=3(x+5) = 3*x + 3*5 = 3x + 15
B= 5(6 - x) = 5*6 + 5*(-x) = 30 - 5x
C= 10(3 + x) = 10*3 + 10*x = 30 + 10x
D=7(x-3) = 7*x + 7*(-3) = 7x - 21
E=4(2x + 3) = 4*2x + 4*3 = ... + ... = ...
F=2(5x-9) = 2*... + 2*.. = ... - ... = ...
