Răspuns:
x=0;1
Explicație:
5•0+2=2
5•1+2=7
x=1,0
5x + 2 = <=7
5x = 7-2
5x = 5 ==>5=1,0
V.:1 x 5 + 2 = 5 + 2 = 7 =7
0 x 5 + 2 = 0 + 2 = 2 <7