bjr
a. 2x =
2 * x = 2 fois x => produit (multiplication)
b. (5x+3)(4-2x)
= (5x+3) fois (4-2x) => produit (multiplication)
c. 5-x = 5 + (-x) => addition
d.(2x+1)au carré = (2x+1) (2x+1) => cf b
e. 2x(3-2x) - 1 = 2x(3-3x) + (-1) => addition
f.x au carré +1 = x² + 1 => addition