pour moi x egale la lettre et * = le fois
a) 5x + 3 = 5 * 8 + 3 = 43
b) 3 * 5x= 3* 5 * 8= 120
c) (x+3)5 = (8+3)5 = 11*5 = 55
d) 10(5+x)= 10(5+8) = 10*13= 130
e) 2x -3y + 2z = 2 * 8 - 3 * 5 + 2 * 1 = 16 - 15 + 2 = 3
f) 6x + 2y - 4z = 6 * 8 + 2 * 5 + 4 * 1 =48 + 10 + 4 = 62
g) 8x + 3 - 3 y= 8 * 8 +3 - 3 * 5 = 64 + 3 - 15 = 67 - 15 = 52
h) x + y ( 3x - 2y) = 8 + 5 ( 3 * 8- 2 * 5) = 13 ( 24 - 10) = 13 * 14 = 182